Zeolite catalyst and method for producing lower olefin

ABSTRACT

A CON zeolite satisfying the following (1) to (2): (1) The framework is CON as per the code specified by the International Zeolite Association (IZA); and (2) It contains silicon and aluminum, and the molar ratio of aluminum to silicon is 0.04 or more.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. application Ser. No. 15/988,744 filed May24, 2018, allowed, which is a continuation of International ApplicationPCT/JP2016/085058, filed on Nov. 25, 2016, which designated the U.S.,and claims priority from Japanese Patent Application 2015-229994 whichwas filed on Nov. 25, 2015, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a zeolite catalyst and a method ofproducing a lower olefin using the same.

BACKGROUND ART

As a method of producing a lower olefin such as ethylene, propylene, andbutene, steam cracking of naphtha, and fluid catalytic cracking ofvacuum gas oil have been heretofore generally carried out. In recentyears a metathesis reaction using ethylene and 2-butene as rawmaterials, and a MTO (methanol to olefin) process using methanol and/ordimethyl ether as a raw material have been known.

Meanwhile, ethylene production by ethane cracking using ethane containedin natural gas as a raw material has been rapidly expanding due torecent price decline of natural gas. However, since ethane crackingscarcely yields hydrocarbons having a carbon number of 3 or more, suchas propylene, butadiene, and butene, unlike steam cracking of naphtha,the shortage of hydrocarbons having a carbon number 3 or more,especially propylene and butadiene, has been surfacing.

Therefore, as a production method by which olefins having a carbonnumber of 3 or more, such as propylene, may be produced selectively, andthe production amount of ethylene is suppressed, a MTO process usingmethanol and/or dimethyl ether synthesized from inexpensive coal ornatural gas as a raw material has been attracting attention.

For example, as disclosed in Patent Document 1 and Non-Patent Literature1, by using a catalyst containing a zeolite having a CON framework(Zeolite CIT-1) as an active ingredient, propylene and butene may beproduced in high yield from methanol and/or dimethyl ether as a rawmaterial, and further by-production of ethylene during propyleneproduction may be suppressed. However, for industrial implementation, acatalyst having even higher performance is required currently.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: JP-A-2013-245163

Non-Patent Literature

-   Non-Patent Literature 1: Am. Chem. Soc. Catal., 5, 4268-4275 (2015)

SUMMARY OF THE INVENTION Problem to be Solved by Invention

By using the CON zeolite catalyst disclosed in Patent Document 1 orNon-Patent Literature 1, propylene and butene may be producedefficiently from methanol and dimethyl ether. In this regard, a CONzeolite catalyst has a structure in which 12-membered ring structuresand 10-membered ring structures intersect in a zigzag manner, such thatpores in three directions do not cross each other at one place.Therefore, the intersection space is small, and therefore it isconceivable that coke is scarcely generate by a reaction, and thereaction activity is not remarkably deteriorated to prolongadvantageously the catalyst life. However, in Patent Document 1 andNon-Patent Literature 1, sufficient investigation has not been made withrespect to the catalyst life of the CON zeolite catalyst, and there isstill room for improvement in terms of the catalyst life. In otherwords, it is preferable to use a zeolite catalyst capable of maintaininga high conversion of raw materials over a long period of time.

An object of the present invention is therefore to provide a zeolitecatalyst capable of maintaining a high conversion of raw materials overa long period of time, and a method of producing a lower olefin stablyover a long period of time using the zeolite catalyst.

Means for Solving the Problem

Regarding prolongation of the life of a CON zeolite catalyst containingaluminum (Al) as a constituent element, the present inventors haveobtained the following knowledge.

(1) A catalyst, in which the ratio ((A₂/A₁)×100 (1)) of the integratedintensity area (A₂) of the signal intensity in a range from 57.5 ppm to70 ppm to the integrated intensity area (A₁) of signal intensity in arange from 45 ppm to 70 ppm is not less than 49.0% when analyzed by²⁷Al-MAS-NMR, has a longer catalyst life than a catalyst with the ratioless than 49.0%.

(2) When the primary particle diameter of the catalyst is smaller, thecatalyst life may be further improved.

The present invention has been made based on the above findings.

That is, the first aspect of the present invention relates to a CONzeolite catalyst comprising aluminum (Al) as a constituent element,wherein the CON zeolite catalyst has a ratio ((A₂/A₁)×100 (%)) of anintegrated intensity area (A₂) of signal intensity in a range from 57.5ppm to 70 ppm to an integrated intensity area (A₁) of signal intensityin a range from 45 ppm to 70 ppm is not less than 49.0% when analyzed by²⁷Al-MAS-NMR.

“A zeolite catalyst comprising aluminum (Al) as a constituent element”means a zeolite in which part of silicon in a silica network issubstituted with aluminum.

“CON zeolite” means a zeolite having a CON type framework according to acode specified by the International Zeolite Association (IZA).

“Zeolite catalyst” means a zeolite in which part of silicon in thesilica network is substituted with another element thereby thesubstituted part constitutes an acid site which has a catalyticfunction. With respect to the zeolite catalyst of the present invention,there is no particular restriction on a reaction where the catalyticfunction, it is preferable as a catalyst for a reaction to produce alower olefin. It is also preferable as a catalyst for a reaction toproduce a lower olefin from organic compounds having carbon number of 1to 10, such as an olefin, an alcohol, and a paraffin, as a rawmaterials, more preferable as a catalyst for a reaction to produceethylene, butene, hexane, ethanol, methanol, and dimethyl ether from thesame raw materials, and further preferable as a catalyst for a reactionto produce methanol and/or dimethyl ether from the same raw materials.

“Signal intensity” and “integrated intensity area” are obtained when azeolite catalyst is analyzed by ²⁷Al-MAS-NMR under the followingconditions. That is, after a zeolite catalyst is sampled and placed intoa solid-state NMR sample tube, the zeolite catalyst is left to standovernight or longer in a desiccator containing a saturated aqueoussolution of ammonium chloride to sufficiently absorb moisture, thenafter tight closure of the sample tube, subjected to an analysis withVarian NMR Systems 400 WB, using a Single Pulse measurement method witha pulse width of 1 μs (equivalent to 22.5° pulse), a MAS rotationfrequency of 12 kHz, a waiting time of 0.1 s, a spectral width of 250kHz, a measurement temperature of room temperature, and a cumulativenumber of 36000 times to obtain a NMR spectrum based on a referencematerial of a 1.0 M aluminum chloride aqueous solution (−0.10 ppm), andthe signal intensity and integrated intensity area are calculated.

In the first aspect of the present invention, it is preferable that theaverage primary particle diameter is 1000 nm or less.

Both “primary particle diameter” and “average primary particle diameter”may be determined with a scanning electron microscope (SEM).

A “primary particle” refers to a smallest particle in which a grainboundary is not recognizable. When an SEM image of a zeolite catalyst istaken, the smallest particle, which belongs to a portion of zeolite inthe SEM image, and in which a grain boundary is not recognized, isherein regarded as a “primary particle”. In this regard, it is notnecessary for primary particles to be present as independent particles,and they may form a secondary particle by aggregation or otherwise. Evenif a secondary particle is formed, it is possible to distinguish primaryparticles on the surface of a secondary particle in the SEM image.

An “average primary particle diameter” is measured as follows. Namely,50 primary particles included in an SEM image of a zeolite catalyst arerandomly selected, the major axis length (the length of the longest linesegment joining one edge and another edge of the primary particle) ismeasured for each of the selected 50 primary particles, and thearithmetic mean of the measured 50 major axis lengths is defined as the“average primary particle diameter”. However, when the entire zeolitecatalyst includes less than 50 primary particles, the respective majoraxis lengths of all the primary particles included in the zeolitecatalyst are measured, and the mean value of them is deemed as the“average primary particle diameter”.

In the first aspect of the present invention, the molar ratio (Si/Al) ofsilicon (Si) to aluminum (Al) is preferably 10 or more.

In the first aspect of the present invention, a zeolite catalyst ispreferably a catalyst used for a reaction to form a lower olefin.

A second aspect of the present invention is a method of producing alower olefin including a step of making a raw material containingmethanol and/or dimethyl ether come into contact with the zeolitecatalyst.

“Lower olefin” means ethylene, propylene, and butene. It is preferablethat the portion of propylene and butene is higher.

Effect of the Invention

According to the present invention, there may be provided a zeolitecatalyst capable of maintaining a high conversion of raw materials overa long period of time, and a method of producing a lower olefin stablyover a long period of time by using the zeolite catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart showing an example of a ²⁷Al-MAS-NMR spectrum of a CONzeolite catalyst (aluminosilicate) according to the present embodiment,and an example of a ²⁷Al-MAS-NMR spectrum of a conventional CON zeolitecatalyst (aluminosilicate).

FIG. 2 is a chart showing powder X-ray diffraction results of thezeolite catalysts according to Examples 1 to 4, and Comparative Examples1 to 5.

FIG. 3 is a chart showing ²⁷Al-MAS-NMR spectra of the zeolite catalystsaccording to Examples and Comparative Examples.

FIG. 4 is an SEM image of the zeolite catalyst according to Example 1.

FIG. 5 is a chart showing powder X-ray diffraction results of thezeolite catalysts according to Examples 5 and 6.

FIG. 6 is an XRD pattern of the CON zeolite obtained in Example A1.

FIG. 7 is an SEM image of the CON zeolite obtained in Example A13.

FIG. 8 is a temperature-programmed desorption profile of toluene withrespect to the CON zeolite according to Example A18.

FIG. 9 is a temperature-programmed desorption profile of toluene withrespect to the BEA zeolite according to Comparative Example A2.

FIG. 10 is temperature-programmed desorption profiles of toluene withrespect to the CON zeolites according to Example A19 and ComparativeExample A3.

DESCRIPTION OF EMBODIMENTS 1. Zeolite Catalyst

A zeolite catalyst according to the present embodiment is a CON zeolitecatalyst containing aluminum (Al) as a constituent element, wherein theCON zeolite catalyst has the ratio ((A₂/A₁)×100 (%))) of the integratedintensity area (A₂) of signal intensity in a range from 57.5 ppm to 70ppm to the integrated intensity area (A₁) of signal intensity in a rangefrom 45 ppm to 70 ppm is not less than 49.0% when analyzed by²⁷Al-MAS-NMR.

1.1. Composition 1.1.1. Aluminum (Al)

A zeolite catalyst according to the present embodiment contains aluminum(Al) as a constituent element. Namely, it has a constitution, where in asilica network of zeolite, part of silicon is substituted with aluminum,and a site substituted by aluminum constitutes an acid site andfunctions as a catalyst. In this regard, in a zeolite catalyst accordingto the present invention, the site of aluminum in the zeolite frameworkmay be different from the conventional one.

FIG. 1 shows an example of a ²⁷Al-MAS-NMR spectrum of a zeolite catalystaccording to the present embodiment, and an example of a ²⁷Al-MAS-NMRspectrum of a conventional zeolite catalyst. As shown in FIG. 1, in thezeolite catalyst according to present embodiment, the peak top of thepeak present in a range from 50 ppm to 65 ppm is shifted from theposition P₂ to the position P₁ as compared with a conventional zeolitecatalyst.

As described above, a zeolite catalyst according to the presentembodiment exhibits a shifted position of the peak attributable toaluminum in the zeolite framework to give the above-mentioned A₂/A₁value different from that of a conventional zeolite catalyst. That is, azeolite catalyst according to the present embodiment is in partcharacterized in that the ratio of the integrated intensity areas((A₂/A₁)×100 (%)) is 49.0% or more. The ratio is preferably 49.5% ormore, more preferably 50.0% or more, and especially preferably 51.0% ormore. Although there is no particular restriction on the upper limit ofthe ratio, it is usually 100.0% or less, preferably 90.0% or less, andmore preferably 80.0% or less.

In a zeolite catalyst according to the present embodiment, the molarratio (Si/Al) of silicon (Si) to aluminum (Al) is preferably 10 or more,more preferably 20 or more, further preferably 50 or more, andespecially preferably 100 or more. It is preferably 1500 or less, morepreferably 1000 or less, and especially preferably 750 or less. Bylimiting the Si/Al within such a range, it is possible to obtain azeolite catalyst having sufficient catalytic activity, and at the sametime having an improved catalyst life.

1.1.2. Elements Other than Al

A zeolite catalyst according to the present embodiment may furtherinclude one or more constituent elements selected from boron (B), zinc(Zn), and germanium (Ge). By including the elements, a CON zeolite maybe easily synthesized. As described later, a zeolite catalyst accordingto the present embodiment may be produced easily by removing part ofboron and zinc from the framework of borosilicate, borozincosilicate,zincosilicate, or the like, and introducing aluminum into the site.Also, from this viewpoint, boron, etc. may remain in the zeolitecatalyst.

Although there is no particular restriction on the molar ratio (Si/B) ofsilicon (Si) to boron (B) in a zeolite catalyst according to the presentembodiment, it is preferably 50 or more, more preferably 100 or more,and especially preferably 200 or more. Although there is also noparticular restriction on the molar ratio (Si/Zn) of silicon (Si) tozinc (Zn), it is preferably 50 or more, more preferably 100 or more, andespecially preferably 200 or more. Although there is also no particularrestriction on the molar ratio (Si/Ge) of silicon (Si) to germanium(Ge), it is preferably 50 or more, more preferably 100 or more, andespecially preferably 200 or more. In addition, there is no particularrestriction on the molar ratio (Si/(B+Zn)) of silicon (Si) to the totalof the above B element and Zn element (B+Zn), it is preferably 50 ormore, more preferably 100 or more, and especially preferably 200 ormore. Furthermore, there is no particular restriction on the molar ratio(Si/(B+Zn+Ge)) of silicon (Si) to the total of the above B element, Znelement, and Ge element (B+Zn+Ge), it is preferably 50 or more, morepreferably 100 or more, and especially preferably 200 or more. The upperlimits of the molar ratios (Si/B), (Si/Zn), (Si/Ge), (Si/(B+Zn)), and(Si/(B+Zn+Ge)) may be, for example, 100000 or less, 50000 or less, or10000 or less. By adjusting the molar ratio of silicon to the element(s)within such a range, it becomes possible to introduce aluminum easily tovacant sites after removing part of boron or zinc from the framework.

Further, a zeolite catalyst according to the present embodiment mayinclude gallium (Ga), iron (Fe), and the like, in addition to aluminum,as a constituent element which substitutes silicon and functions as anacid site.

1.2. Crystal Structure

It is important that a zeolite catalyst according to the presentembodiment has a CON type framework as per the code specified by theInternational Zeolite Association (IZA). A CON zeolite catalyst has as aconstitutional unit, a 3-dimensional pore structure in which two12-membered ring structures and one 10-membered ring structure crosseach other. The CON zeolite catalyst having the 12-membered ringstructures is more advantageous to pore diffusion of a reaction productthan a CHA zeolite constituted solely with 8-membered ring structures,or an MFI zeolite constituted solely with 10-membered ring structures,so as to form a catalyst superior in selectivity for an olefin with acarbon number of 3 or more. Meanwhile, a CON zeolite catalyst has anadvantage that the catalyst life is long, conceivably because the poresin three directions do not intersect at one place, and an intersectionspace is small, so that coke is less likely to be formed by a reactionand remarkable deterioration of the reaction activity is less likely tobe incurred. In addition to the above feature, the site of aluminum inthe crystal structure according to the present embodiment may bedifferent from a conventional site, and the catalyst life may be furtherimproved.

Whether a zeolite catalyst has a CON framework or not may be judged byperforming an X-ray diffraction analysis using CuKα as a radiationsource and matching the obtained profile with the profiles registered inthe X-ray diffraction intensity database (PDF #00-050-1694). Accordingto the database, a diffraction peak attributed to the (130) plane is tobe recognized in the vicinity of 2θ=20.4°, and a diffraction peakattributed to the (510) plane is to be recognized in the vicinity of2θ=22.1°.

As described below, the size of a primary particle in a zeolite catalystaccording to the present embodiment is small. The size of a primaryparticle in a zeolite catalyst affects the half width of a diffractionpeak in a powder X-ray diffraction analysis. In other words, the smallerthe primary particle becomes, the larger the half width tends to become.

From this point of view, in a zeolite catalyst according to the presentembodiment, the half width of the peak attributable to the (130) planeobtained by a powder X-ray diffraction analysis (Radiation source: CuKα,reading width: any width from 0.015° to 0.020°, and scanning speed: anyspeed from 2.0°/min to 20.0°/min) is preferably from 0.10° to 0.25°. Itis more preferably 0.12° or more, further preferably 0.14° or more, andespecially preferably 0.16° or more. Further, it is more preferably0.22° or less, and especially preferably 0.20° or less.

In addition, in a zeolite catalyst according to the present embodiment,the half width of the peak attributable to the (510) plane obtained by apowder X-ray diffraction analysis (Radiation source: CuKα, readingwidth: any width in a range from 0.015° to 0.020°, and scanning speed:any speed in a range from 2.0°/min to 20.0°/min) is preferably from0.10° to 0.25°. It is more preferably 0.12° or more, further preferably0.14° or more, and especially preferably 0.16° or more. Further, it ismore preferably 0.22° or less, and especially preferably 0.20° or less.

When it is 0.10° or more, the primary particle tends to be small, whichis preferable. When it is 0.25° or less, the primary particle is largeenough not to contain an amorphous part, which is also preferable. Inthis regard, the “half width of the peak of the (130) plane”, and “thehalf width of the peak of the (510) plane” in the present embodiment arevalues obtained by the following method. Namely, firstly from theobtained diffraction profile, a diffraction peak near 20=20.4°attributable to the (130) plane and a diffraction peak near 20=22.1°attributable to the (510) plane are detected. Then, the peak is cut outin the range of 19° to 26°, and after performing subtraction of thebackground and making Kα1 and Kα2 separation, the half width of Kα1 isread. For this analysis, an analysis software “JADE” is used. In thisregard, the half width means the width of 2θ at an intensity half themaximum intensity of the peak.

1.3. Shape

There is no particular restriction on the shape of a zeolite catalystaccording to the present embodiment, and it may be particulate (powdery)or massive form, or may be formed to various shapes using a materialinert to the reaction or a binder. Examples of the material inert to thereaction or the binder include alumina or alumina sol, silica, silicagel, a silicate, quartz, and mixtures thereof. Among them, alumina ispreferable from the viewpoint that a firm formed article may be formedas an industrial catalyst. Addition of these materials is effective inreducing the cost of a whole catalyst and acting as a heat sink forassisting thermal shield during regeneration of the catalyst, and alsoeffective in increasing the density of the catalyst, and increasing thecatalyst strength.

In particular, it is preferable that a zeolite catalyst according to thepresent embodiment is composed of small primary particles. When theprimary particle is reduced in size by suppressing the crystal growth asabove, the catalyst life may be further improved.

Specifically, a zeolite catalyst according to the present embodimentpreferably has an average primary particle diameter of 1000 nm or less,more preferably 700 nm or less, further preferably 300 nm or less, andespecially preferably 200 nm or less. Although there is no particularrestriction on the lower limit of the average primary particle diameter,it is usually 20 nm or more, preferably 40 nm or more, and especiallypreferably 60 nm or more. The definition of a primary particle diameterand the calculation method of an average primary particle diameter areas described above. When the primary particle is small, the primaryparticles are likely to agglomerate and form secondary particles.However, even if secondary particles are formed, it is possible todistinguish each primary particle existing on the surface of a secondaryparticle in an SEM image, and the average primary particle diameter maybe calculated.

There is no particular restriction on the BET specific surface area of azeolite catalyst according to the present embodiment, and it is usually200 m²/g or more, preferably 250 m²/g or more, and more preferably 300m²/g or more; and is usually 1000 m²/g or less, preferably 800 m²/g orless, and more preferably 700 m²/g or less.

There is no particular restriction on the pore volume of a zeolitecatalyst according to the present embodiment, and it is usually 0.1 mL/gor more, and preferably 0.2 mL/g or more; and is usually 3 mL/g or less,and preferably 2 mL/g or less.

1.4. Others

There is no particular restriction on the ion exchange site of a zeolitecatalyst according to the present embodiment, and it may be an H type ora site exchanged with a metal ion. Examples of the metal ion include analkali metal ion and an alkaline earth metal ion.

As described above, in a zeolite catalyst according to the presentinvention, the site of aluminum in the zeolite framework may bedifferent from the conventional site, and the above ratio ((A₂/A₁)×100(%)) is 49.0% or more. As a result, the catalyst life is improved ascompared with a catalyst having the ratio of less than 49.0%. Inaddition, when the primary particle diameter of the zeolite catalyst issmall (or when the half width of the X-ray diffraction peak is large),the catalyst life is further improved.

2. Method of Producing Zeolite Catalyst

A zeolite catalyst according to the present embodiment may be producedeasily by a method in which, for example, a CON type crystallineborosilicate containing at least boron (B) as a constituent element issynthesized, then B in the framework is removed, and Al is introduced inat least part of vacant sites (post-treatment method).

2.1. Synthesis of Crystalline Borosilicate

The crystalline borosilicate may be synthesized by a hydrothermalsynthesis method. For example, an alkali metal source, a boron source,and a structure-directing agent (preferably N, N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide) are added to water andstirred, then a silica source is added thereto to form a uniform gel,and the obtained raw material gel is kept in a pressurized heatingvessel at 120 to 200° C. to be crystallized. In this connection, fromthe viewpoint of producibility, it is preferable to add a seed crystalat the time of crystallization. Next, after filtration and washing ofthe crystallized raw material gel, the solid content is dried at 100 to200° C., and subsequently calcined at 400 to 900° C. to obtain powderycrystalline borosilicate.

In this regard, as an alkali metal source, one or more selected fromhydroxides, chlorides, bromides, iodides, hydrogencarbonates,carbonates, and the like of lithium, sodium, potassium, rubidium, andcesium may be used. As a boron source, one or more selected from boricacid, sodium borate, boron oxide, and the like may be used. As a silicasource, one or more selected from a silicate, such as fumed silica,silica sol, silica gel, silicon dioxide, and water glass, an alkoxide ofsilicon, such as tetraethoxyorthosilicate and tetramethoxysilane, ahalide of silicon, and the like may be used.

Incidentally, the crystalline borosilicate may contain zinc (Zn),aluminum (Al), gallium (Ga), iron (Fe), etc. as a constituent element inaddition to boron (B). Namely, a crystalline borozincosilicate, acrystalline boroaluminosilicate, a crystalline borogallosilicate, acrystalline boroferrisilicate, or the like may be used instead of acrystalline borosilicate. In this case, in addition to the boron sourceor the silica source, a zinc source, an aluminum source, a galliumsource, and an iron source may be added in forming the gel.

In this case, as the zinc source, one or more selected from zincacetate, zinc sulfate, zinc nitrate, zinc hydroxide, and the like may beused. As the aluminum source, one or more selected from aluminumsulfate, aluminum nitrate, pseudoboehmite, an aluminum alkoxide,aluminum hydroxide, alumina sol, sodium aluminate, and the like may beused. As the gallium source, one or more selected from gallium nitrate,gallium sulfate, gallium phosphate, gallium chloride, gallium bromide,gallium hydroxide, and the like may be used. As the iron source, one ormore selected from iron nitrate, iron sulfate, iron oxide, ironchloride, iron hydroxide, and the like may be used.

As a seed crystal, a BEA-type, a CON-type, an MSE-type zeolite, and thelike may be used. As the seed crystal, either a zeolite which contains astructure-directing agent, but is not calcined after hydrothermalsynthesis, or a zeolite which is calcined but does not contain astructure-directing agent, may be used. There is no particularrestriction on the composition of a zeolite to be used as a seedcrystal, insofar as it does not greatly affect the composition of themixture. Although there is no particular restriction on the particlediameter of a zeolite to be used as a seed crystal, it is preferablyfrom 20 nm to 2000 nm in terms of an average primary particle diameter.It is preferably 40 nm or more, and more preferably 1000 nm or less.When the average primary particle diameter of a seed crystal is adjustedwithin the above range, dissolution of a seed crystal in the mixtureproceeds sufficiently, and crystallization of a CON zeolite may bepromoted.

In the synthesis of the crystalline borosilicate (crystallineborozincosilicate, crystalline boroaluminosilicate, crystallineborogallosilicate, and crystalline boroferrisilicate), the molar ratio(Si/B) of silicon (Si) to boron (B) is preferably 50 or less, morepreferably 30 or less, further preferably 20 or less, and especiallypreferably 10 or less. It has been found that by charging raw materialsat a low Si/B ratio, the primary particle of a CON zeolite becomessmaller and the catalyst life is improved. Although there is noparticular restriction on the lower limit of the molar ratio (Si/B), itis preferably 3 or more, and more preferably 5 or more.

Although there is no particular restriction on the molar ratio (Si/Zn)of silicon (Si) to zinc (Zn) in the raw material mixture in synthesizinga crystalline borozincosilicate, it is preferably from 50 to 400. Thelower limit is more preferably 75 or more, and especially preferably 100or more, and the upper limit is more preferably 250 or less, andespecially preferably 150 or less.

Although there is no particular restriction on the molar ratio (Si/Ge)of silicon (Si) to germanium (Ge) in the raw material mixture insynthesizing a crystalline borogermanosilicate, it is preferably from 5to 100. The lower limit is more preferably 7 or more, and especiallypreferably 10 or more; and the upper limit is more preferably 75 orless, and especially preferably 50 or less.

The molar ratio (M/Si) of an alkali metal element (M) to silicon (Si) inthe raw material mixture is preferably from 0 to 0.3. The lower limit ismore preferably 0.05 or more, and especially preferably 0.08 or more,and the upper limit is more preferably 0.20 or less, and especiallypreferably 0.12 or less. By adjusting the M/Si within the above range,crystallization of a CON zeolite is promoted and the zeolite may besynthesized in high yield.

The molar ratio (SDA/Si) of a structure-directing agent (SDA) to silicon(Si) in the raw material mixture is preferably from 0 to 0.5, morepreferably 0.10 or more, and especially preferably 0.20 or more; andmore preferably 0.40 or less, and especially preferably 0.30 or less. Byadjusting the SDA/Si within the above range, crystallization of a CONzeolite is promoted, and the zeolite may be synthesized in high yield.In addition, the cost of the raw material (structure-directing agent)may be suppressed.

Although there is no particular restriction on the proportion of waterin the raw material mixture, the molar ratio (H₂O/Si) of water (H₂O) tosilicon (Si) is preferably from 10 to 100. It is more preferably 15 ormore, and especially preferably 20 or more; and is more preferably 60 orless, and especially preferably 30 or less. When the proportion of waterin the mixture is within the above range, it is possible to suppressdeterioration of mixability in stirring due to viscosity increase duringa reaction. Further, the productivity per reactor may be increased.

Although there is no particular restriction on the proportion of a seedcrystal in the raw material mixture, the molar ratio (Seed/Si) of a seedcrystal (Seed) to silicon (Si) is preferably from 0 to 0.10, morepreferably 0.01 or more, and especially preferably 0.02 or more; and ismore preferably 0.05 or less, and especially preferably 0.03 or less.When the amount of the seed crystal is within the above range, theamount of a precursor directed to the CON framework becomes sufficient,and crystallization may be promoted. In addition, since the content of acomponent derived from the seed crystal in the product is suppressed andthe productivity may be enhanced, so that the production cost may bereduced.

Although there is no particular restriction on the hydrothermalsynthesis temperature, it is preferably from 120° C. to 200° C., morepreferably 150° C. or higher, and especially preferably 160° C. orhigher; and is more preferably 190° C. or lower, and especiallypreferably 180° C. or lower. By adjusting the reaction temperaturewithin the above range, the crystallization time of a CON zeolite may beshortened. Further, a zeolite with small sized primary particles may besynthesized.

Although there is no particular restriction on the hydrothermalsynthesis time, it is preferably from 12 hours to 20 days. The lowerlimit is more preferably 1 day or more, and especially preferably 3 daysor more; and the upper limit is more preferably 14 days or less, andespecially preferably 9 days or less.

2.2. Removal of B and Introduction of Al

There is no particular restriction on a method of removing B from theframework of a crystalline borosilicate, and a conventionally knownmethod, such as acid a treatment and a steam treatment, may be adopted.The same is true for a method of removing B and Zn from a crystallineborozincosilicate, a method of removing B from a crystallineborogallosilicate, a method of removing B from a crystallineboroaluminosilicate, and a method of removing B from a crystallineboroferrisilicate.

There is no particular restriction on a method of introducing Al to acrystalline borosilicate, from which B has been removed, into at leastpart of the sites deprived of B. For example, there is a method in whicha crystalline borosilicate after removal of B is added together with analuminum source to water, which is stirred and then heated. In thiscase, as an aluminum source, any one appropriately selected from theabove may be used.

The molar ratio (Si/Al) of silicon (Si) to aluminum (Al) during apost-treatment is preferably from 10 to 1500. The lower limit is morepreferably 50 or more, and especially preferably 100 or more; and theupper limit is more preferably 1000 or less, and especially preferably750 or less. By adjusting the Si/Al within the range, it is possible toobtain a zeolite catalyst having sufficient catalytic activity andhaving a further improved catalyst life.

Although there is no particular restriction on the heating temperature,it is preferably from 60° C. to 200° C. The lower limit is morepreferably 80° C. or higher, and especially preferably 100° C. orhigher; and the upper limit is more preferably 175° C. or lower, andespecially preferably 150° C. or lower.

2.3. Other Post-Treatment Methods

In the above post-treatment method, a method of introducing Al afterremoving boron from a crystalline borosilicate has been described. Inaddition, it is possible to perform a post-treatment method, in which asilicate containing zinc (Zn), a silicate containing germanium (Ge), orthe like is synthesized in advance, the zinc, germanium, or the like isremoved, and then Al is introduced.

In this case, the synthesis of the silicate containing zinc (Zn), thesilicate containing germanium (Ge), etc. may be carried out as in 2.1.,and the removal of Zn, Ge, etc. and introduction of Al may be carriedout as in 2.2.

Examples of an element which may be contained in a silicate includeelements in the fourth period of the periodic table, elements in groups12 to 15 in the periodic table, or elements satisfying both of them,which example is zinc or germanium. An exemplar molar ratio of the aboveelements in a zeolite catalyst according to the present embodiment isthe same as the aforedescribed Si/Zn ratio and Si/(B+Zn) ratio. Anexemplar molar ratio of the above elements in the raw material mixtureis the same as the Si/Zn ratio in the synthesis of a crystallineborozincosilicate, or the Si/Ge ratio in the synthesis of a crystallineborogermanosilicate synthesis. Two or more of the above elements may beused in combination. It is conceivable that the above element occupies aspecific site in the zeolite framework, and the element at such aspecific site (for example, a site different from the conventional site)is replaced with aluminum to yield a zeolite according to the presentembodiment.

On the other hand, when the molar ratio (Si/Al) of a zeolite catalyst isadjusted within a specific range (for example, the lower limit is set ata specific value), a zeolite catalyst according to the presentembodiment may be also obtained. In this case, the molar ratio (Si/Al)of a zeolite catalyst according to the present embodiment may be higherthan 100, higher than 130, higher than 170, higher than 200, higher than230, or higher than 250, while an exemplar upper limit is as describedabove. When the zeolite catalyst is produced, the molar ratio (Si/Al) ofsilicon (Si) to aluminum (Al) during a post-treatment (representingherein the molar ratio of Si in a silicate to be subjected to apost-treatment to Al in an aluminum source to be used in thepost-treatment method) may be higher than 150, higher than 200, higherthan 250, higher than 300, and higher than 350. Meanwhile, an exemplarupper limit is as described above.

When a silicate contains the above element, such as zinc and germanium,or when the molar ratio (Si/Al) in a zeolite catalyst is increased, azeolite catalyst according to the present embodiment tends to beobtained easily, even if the Si/B ratio in the raw material mixture forthe silicate is not low (for example, when the Si/B ratio is higher than10, or higher than 20).

A zeolite catalyst according to the present embodiment may be producedby a combination of 2 or more methods of the method in which rawmaterials are charged at a low Si/B ratio, the method including elementssuch as zinc and germanium, and the method in which the molar ratio(Si/Al) is adjusted at a high level.

Although the methods of producing a zeolite catalyst according to thepresent invention by a post-treatment method have been described above,a method of producing a zeolite catalyst according to the presentembodiment is not limited to a post-treatment method.

3. Method of Producing Lower Olefin

Another aspect of the present invention is a method of producing a lowerolefin by the MTO method. In other words, it is a method of producing alower olefin involving a step of making a raw material containingmethanol and/or dimethyl ether come into contact with a zeolite catalystaccording to the present embodiment. Lower olefin refers to ethylene,propylene, and butene. Particularly, those containing large amounts ofpropylene and butene are preferable.

The lower olefin produced according to the present embodiment maycontain, for example, propylene at a content of 30 to 70 mol %, buteneat a content of 10 to 40 mol %, and ethylene at a content of 1 to 15 mol%.

Since details of methanol or dimethyl ether as a raw material, reactionprocedures, and reaction conditions for the MTO method are publiclyknown, detailed explanation is omitted herein. For example, [methanol,and dimethyl ether], and [reaction procedures, and conditions] disclosedin Patent Document 1 (Japanese Unexamined Patent Application PublicationNo. 2013-245163) may be adopted.

Since a zeolite catalyst having an improved catalyst life is used in theproduction method of a lower olefin according to the present embodiment,it is possible to produce a lower olefin stably over a long period oftime.

EXAMPLE

Hereinafter, the present invention will be described specifically belowreferring to examples, provided that the present invention be notlimited in any way to the following examples.

1. Synthesis of CON Zeolite Catalyst (Aluminosilicate) Example 1(Synthesis of Crystalline Borosilicate)

Firstly, 0.81 g of a 1.0 M sodium hydroxide aqueous solution, 1.18 g ofan aqueous solution of 1.05 M N, N, N-trimethyl-(−)-cis-myrtanylammoniumhydroxide (hereinafter abbreviated as “TMMAOH”), and 1.99 g of waterwere mixed, thereto 0.0825 g of boric acid was added, and the mixturewas stirred, to which 0.405 g of fumed silica (Cab-O-Sil M-7D, producedby Cabot Corporation) was added as a silica source, and further stirredsufficiently. Further, 0.0081 g of BEA type borosilicate was added as aseed crystal, and the mixture was stirred to prepare a reaction mixture(hereinafter occasionally referred to as “raw material gel”).

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 9 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.397 g of a sodium type zeolite powder (borosilicate).

(Removal of B and Introduction of Al)

The following operation (post-treatment) was carried out for the purposeof removing boron in the zeolite framework of the obtained borosilicateand replacing it with aluminum. Into 20 mL of a 2 N nitric acid aqueoussolution, 0.2 g of the obtained borosilicate was added, and the mixturewas stirred at 100° C. at reflux for 20 hours. Thereafter, the zeolitewas filtrated, washed with water, and then dried at 100° C. overnight toyield a protonic zeolite powder (silicate). The whole amount of theyielded powder was added to 20 g of an aqueous solution having dissolved0.0031 g of aluminum nitrate nonahydrate, and the mixture was stirred at100° C. at reflux for 2 days. Thereafter, the zeolite was filtrated,washed with water, and then dried at 100° C. overnight to obtain 0.154 gof a protonic zeolite powder (aluminosilicate).

Example 2 (Synthesis of Crystalline Borozincosilicate)

Firstly, 0.54 g of a 1.0 M sodium hydroxide aqueous solution, 0.79 g ofa 1.05 M TMMAOH aqueous solution, and 1.43 g of water were mixed,thereto 0.0275 g of boric acid, and 0.0041 g of zinc acetate were added,and the mixture was stirred, to which 0.27 g of fumed silica (Cab-O-SilM-7D, produced by Cabot Corporation) was added as a silica source, andfurther stirred sufficiently. Further, 0.0054 g of a BEA typeborosilicate was added as a seed crystal, and the mixture stirred toprepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 7 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.213 g of a sodium type zeolite powder (borozincosilicate).

(Removal of B and Zn, and Introduction of Al)

The post-treatment was carried out for the purpose of removing boron andzinc in the zeolite framework of the obtained borozincosilicate andreplacing them with aluminum. The post-treatment was carried out in thesame manner as in Example to obtain 0.162 g of a protonic zeolite powder(aluminosilicate).

Example 3 (Synthesis of Crystalline Borozincosilicate)

Firstly, 0.45 g of a 1.0 M sodium hydroxide aqueous solution, 0.79 g ofa 1.05 M TMMAOH aqueous solution, and 1.43 g of water were mixed,thereto 0.011 g of boric acid, and 0.0082 g of zinc acetate were added,and the mixture was stirred, to which 0.27 g of fumed silica (Cab-O-SilM-7D, produced by Cabot Corporation) was added as a silica source, andfurther stirred sufficiently. Further, 0.0054 g of a BEA typeborosilicate was added as a seed crystal and the mixture stirred toprepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 7 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.228 g of a sodium type zeolite powder (borozincosilicate).

(Removal of B and Zn, and Introduction of Al)

The post-treatment was carried out for the purpose of removing boron andzinc in the zeolite framework of the obtained borozincosilicate andreplacing them with aluminum. The post-treatment was carried out in thesame manner as in Example 1 to obtain 0.151 g of a protonic zeolitepowder (aluminosilicate).

Example 4 (Synthesis of Crystalline Boroaluminosilicate)

Firstly, 0.36 g of a 1.0 M sodium hydroxide aqueous solution, 0.79 g ofa 1.05 M TMMAOH aqueous solution, and 0.72 g of water were mixed,thereto 0.011 g of boric acid, and 0.0109 g of aluminum sulfate wereadded, and the mixture was stirred, to which 0.27 g of fumed silica(Cab-O-Sil M-7D, produced by Cabot Corporation) was added as a silicasource, and further stirred sufficiently. Further, 0.0054 g of a BEAtype borosilicate was added as a seed crystal, and the mixture wasstirred to prepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 200° C. for 2 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.260 g of a sodium type zeolite powder (boroaluminosilicate).

(Removal of B and Introduction of Al)

The post-treatment was carried out for the purpose of removing boron inthe zeolite framework of the obtained borosilicate and replacing it withaluminum. Into 25 mL of a 2 N nitric acid aqueous solution, 0.25 g ofthe obtained boroaluminosilicate was added, and the mixture was stirredat 100° C. at reflux for 20 hours. Thereafter, the zeolite wasfiltrated, washed with water, and then dried at 100° C. overnight toyield a protonic zeolite powder (aluminosilicate). The whole amount ofthe yielded powder was added to 20 g of an aqueous solution havingdissolved 0.0010 g of aluminum nitrate nonahydrate, and the mixture wasstirred at 100° C. at reflux for 2 days. Thereafter, the zeolite wasfiltrated, washed with water and then dried at 100° C. overnight toobtain 0.175 g of a protonic zeolite powder (aluminosilicate).

Comparative Example 1

Firstly, 0.54 g of a 1.0 M sodium hydroxide aqueous solution, 0.79 g ofa 1.05 M TMMAOH aqueous solution, and 1.33 g of water were mixed,thereto 0.055 g of boric acid and 0.0030 g of aluminum sulfate wereadded, and the mixture was stirred, to which 0.27 g of fumed silica(Cab-O-Sil M-7D, produced by Cabot Corporation) was added as a silicasource, and further stirred sufficiently. Further, 0.0054 g of a BEAtype borosilicate was added as a seed crystal, and the mixture wasstirred to prepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 10 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.260 g of a sodium type zeolite powder (boroaluminosilicate).

The obtained powder was ion exchanged at 80° C. for 1 hour in a 2Naqueous solution of ammonium nitrate and then filtrated. The powderobtained by filtration was ion-exchanged again in a 2N aqueous solutionof ammonium nitrate at 80° C. for 1 hour, then filtrated and dried toobtain an ammonium type zeolite. Thereafter, it was calcined in an airatmosphere at 600° C. to obtain a protonic zeolite (aluminosilicate).

Comparative Example 2 (Synthesis of Crystalline Borosilicate)

Firstly, 0.9 g of a 1.0 M sodium hydroxide aqueous solution, 1.58 g of a1.05 M TMMAOH aqueous solution, and 7.72 g of water were mixed, thereto0.022 g of boric acid was added, and the mixture was stirred, to which0.54 g of fumed silica (Cab-O-Sil M-7D, produced by Cabot Corporation)was added as a silica source, and further stirred sufficiently. Further,0.0108 g of a BEA type borosilicate was added as a seed crystal, and themixture was stirred to prepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 150° C. for 21 days in a state of being left still. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.438 g of a sodium type zeolite powder (borosilicate).

(Removal of B and Introduction of Al)

The following post-treatment was carried out for the purpose of removingboron in the zeolite framework of the obtained borosilicate andreplacing it with aluminum. Into 40 mL of a 0.01 M hydrochloric acidaqueous solution, 0.4 g of the obtained borosilicate was added, and themixture was stirred at 100° C. at reflux for 24 hours. Thereafter, thezeolite was filtrated, washed with water, and then dried at 100° C.overnight to yield a protonic zeolite powder (silicate). The wholeamount of the yielded powder was added to 17.5 g of an aqueous solutionhaving dissolved 0.70 g of aluminum nitrate nonahydrate, and the mixturewas stirred at 100° C. at reflux for 12 hours. Thereafter, the zeolitewas filtrated, washed with water and then dried at 100° C. overnight toobtain 0.328 g of a protonic zeolite powder (aluminosilicate).

Comparative Example 3

Firstly, 0.45 g of a 1.0 M sodium hydroxide aqueous solution, 0.79 g ofa 1.05 M TMMAOH aqueous solution, and 1.43 g of water were mixed,thereto 0.011 g of boric acid and 0.0038 g of aluminum sulfate wereadded, and the mixture was stirred, to which 0.27 g of fumed silica(Cab-O-Sil M-7D, produced by Cabot Corporation) was added as a silicasource, and further stirred sufficiently. Further, 0.0054 g of a BEAtype borosilicate was added as a seed crystal, and the mixture wasstirred to prepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 7 days in a state of being left still. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.213 g of a sodium type zeolite powder (boroaluminosilicate). Aprotonic zeolite (aluminosilicate) was obtained by conducting subsequention exchange and calcination in the same manner as in Example 5.

Comparative Example 4

A protonic zeolite (aluminosilicate) was yielded by conducting ionexchange and calcination in the same manner as in Comparative Example 1on the sodium type zeolite powder (boroaluminosilicate) obtained afterthe hydrothermal synthesis in Example 4.

Comparative Example 5

The protonic zeolite powder (aluminosilicate) yielded after the nitricacid treatment, filtration and drying in Example 4 was directly used asa zeolite catalyst.

Example 5 (Synthesis of Crystalline Borosilicate)

Firstly, 0.45 g of a 1.0 M sodium hydroxide aqueous solution, 0.63 g ofa 1.32 M TMMAOH aqueous solution, and 1.99 g of water were mixed,thereto 0.011 g of boric acid was added, and the mixture was stirred, towhich 0.27 g of fumed silica (Cab-O-Sil M-7D, produced by CabotCorporation) was added as a silica source, and further stirredsufficiently. Further, 0.0054 g of a BEA type borosilicate was added asa seed crystal, and the mixture was stirred to prepare a raw materialgel.

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 4 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.214 g of a sodium type zeolite powder (borosilicate).

(Removal of B and Introduction of Al)

The post-treatment was carried out for the purpose of removing boron inthe zeolite framework of the obtained borosilicate and replacing themwith aluminum. The post-treatment was carried out in the same manner asin Example to obtain 0.155 g of a protonic zeolite powder(aluminosilicate).

Example 6 (Synthesis of Crystalline Borogermanosilicate)

Firstly, 0.45 g of a 1.0 M sodium hydroxide aqueous solution, 0.63 g ofa 1.32 M TMMAOH aqueous solution, and 1.99 g of water were mixed,thereto 0.011 g of boric acid, and 0.028 g of germanium oxide wereadded, and the mixture was stirred, to which 0.27 g of fumed silica(Cab-O-Sil M-7D, produced by Cabot Corporation) was added as a silicasource, and further stirred sufficiently. Further, 0.0054 g of a BEAtype borosilicate was added as a seed crystal, and the mixture wasstirred to prepare a raw material gel.

The prepared raw material gel was charged into an autoclave and heatedat 170° C. for 5 days with stirring at 40 rpm. The product wasfiltrated, washed with water, and then dried at 100° C. overnight. Afterdrying, it was calcined in an air atmosphere at 600° C. for 6 hours toyield 0.201 g of a sodium type zeolite powder (borogermanosilicate).

(Removal of B and Ge, and Introduction of Al)

The post-treatment was carried out for the purpose of removing boron andgermanium in the zeolite framework of the obtained borogermanosilicateand replacing them with aluminum. The post-treatment was carried out inthe same manner as in Example 1 to obtain 0.162 g of a protonic zeolitepowder (aluminosilicate).

2. Evaluation of Zeolite Catalyst (Aluminosilicate)

For the aluminosilicates according to Examples 1 to 6 and ComparativeExamples 1 to 5, the following evaluations were carried out.

<Elemental Analysis>

Elemental analyses were carried out by inductively-coupled plasma atomicemission spectrometry (ICP-AES). For the analyses, an ICPE-9000 producedby Shimadzu Corporation was used. The compositions of the synthesizedaluminosilicates in Examples 1 to 6 and Comparative Examples 1 to 5 areshown in Table 2.

<X-Ray Diffraction Analysis>

X-ray diffraction (XRD) analyses of the synthesized aluminosilicate werecarried out using a RINT Ultima III produced by Rigaku Corporation. TheX-ray source was CuKα (X-ray output: 40 kV, 40 mA), the reading widthwas 0.02°, and the scanning speed was 20.0°/min. The XRD patternsobtained by analyses are shown in FIG. 2. It was confirmed from FIG. 2that each aluminosilicate according to Examples 1 to 4 or ComparativeExamples 1 to 5 was a zeolite having a CON framework.

The X-ray diffraction (XRD) analyses of the aluminosilicates accordingto Examples 5 and 6 were carried out using an X′PERT PRO MPD produced byMalvern Panalytical B.V. The X-ray source was CuKα (X-ray output: 40 kV,30 mA), the reading width was 0.016°, and the scanning speed was4.0°/min. The XRD patterns obtained by the analyses are shown in FIG. 5.It was confirmed from FIG. 5 that each of the aluminosilicate accordingto Examples 5 and 6 was a zeolite having a CON framework.

<Analysis of Half Width>

An X-ray diffraction (XRD) analysis for measuring a half width wascarried out using an X′ PERT PRO MPD produced by Malvern PanalyticalB.V. The X-ray source was CuKα (X-ray output: 40 kV, 30 mA), the readingwidth was 0.016°, and the scanning speed was 4.0°/min. The “half width”of the peak of the (130) plane” and the “half width of the peak of the(510) plane” obtained from an XRD pattern obtained under the measurementconditions are shown in Table 2.

As obvious from Table 2, a sample having a smaller average primaryparticle diameter tends to have a larger half width. With respect toComparative Example 2, although the average primary particle diameter islarge, the half width is relatively large. This result is conceivablybecause particles partially containing polycrystals were included in thecalculation of an average primary particle diameter with respect to thissample.

<²⁷Al-MAS-NMR>

An analysis of ²⁷Al-MAS-NMR is carried out after placing a sample ofaluminosilicate in a sample tube for NMR, leaving the same standing in adesiccator filled with a saturated aqueous solution of ammonium chlorideovernight for absorbing moisture sufficiently, and then closing the tubehermetically, under the conditions shown in the following Table 1 usinga 1.0 M aluminum chloride aqueous solution as a reference material(−0.10 ppm). With respect to the ²⁷Al-MAS-NMR spectrum obtained by theanalysis, the ratio ((A₂/A₁)×100 (U) of the integrated intensity area(A₂) of the signal intensity in the range from 57.5 ppm to 70 ppm to theintegrated intensity area (A₁) of the signal intensity in the range from45 ppm to 70 ppm was calculated. The results are shown in Table 2.

TABLE 1 Apparatus Varian NMR Systems 400 WB produced by Agilent ProbeProbe for CP/MAS: 4 mmϕ) T3HX Observed nucleus ²⁷Al Measurement methodSingle Pulse method Resonant frequency 104.18 MHz Pulse width 1 μs(equivalent to 22.5° pulse) MAS rotation speed 12 kHz Waiting time 0.1sec Spectral width 250 kHz Measurement temperature Room temperatureCumulative number 36000 times Reference material 1.0M aluminum chlorideaqueous solution (−0.10 ppm)

<Scanning Electron Microscope>

A measurement with a scanning electron microscope (SEM) was carried outusing an S-5200 produced by Hitachi High-Technologies Corporation. Fromthe obtained SEM image, 50 primary particles were randomly extracted,and the major axis lengths of the particles were measured as theparticle diameters. The arithmetic mean of the obtained particlediameters was defined as the average primary particle diameter. Theresults are shown in Table 2. For reference, FIG. 4 shows an SEM imageof the zeolite catalyst according to Example 1. As shown in FIG. 4, inthe zeolite catalyst according to Example 1, fine primary particlesaggregate to form a secondary particle.

<Production of Lower Olefin>

Production of lower olefin was carried out using a CON zeolite catalystobtained in Examples 1 to 6 and Comparative Examples 1 to 5.

For the reaction, a quartz reaction tube having an inner diameter of 4mm was filled with 100 mg of each zeolite having a CON frameworkobtained in Examples 1 to 6 and Comparative Examples 1 to 5, using anormal pressure fixed bed flow reactor. A mixed gas of 50.0 mold ofmethanol and 50.0 mold of helium was supplied to the reactor, such thatthe weight hourly space velocity of methanol was 15 hr⁻¹, and a reactionwas conducted at 450° C. and 0.1 MPa (absolute pressure). The productwas analyzed by gas chromatography every 1 hour or 2 hours from thestart of the reaction (with respect to Example 1 every 2 hours or 4hours). The methanol conversion, and the ethylene selectivity, propyleneselectivity, and butene selectivity after 2 hours from the start of thereaction are shown in Table 2. In this regard, a methanol conversionmeans herein a conversion of methanol alone without dimethyl ether.Further, the catalyst life L₁ and the catalyst life L₂ shown in Table 2are defined respectively as the time periods in which the methanolconversion is maintained at 95% or more, or 90% or more.

TABLE 2 Comparative Comparative Example 1 Example 2 Example 3 Example 4Example 1 Example 2 Initial charge TMMAOH/Si 0.2 0.2 0.2 0.2 0.2 0.2composition NaOH/Si 0.12 0.12 0.1 0.08 0.12 0.1 (molar ratio) H₂O/Si 3030 30 20 30 60 H₃BO₃/Si 0.2 0.1 0.04 0.04 0.2 0.04 (CH₃COO)₂Zn/ — 0.0050.01 — — — Si GeO₂/Si — — — — — — Al₂(SO₄)₃/Si — — — 0.007 0.002 —Seed/Si 0.02 0.02 0.02 0.02 0.02 0.02 Post-treatment H₂O/Si 333 333 333333 — 167 composition Al(NO₃)₃/Si 0.0025 0.0025 0.0025 0.005 — 0.33(molar ratio) Zeolite Si/Al 399 276 289 109 228 99 catalyst Si/B 3893438 n.d 448 17 745 composition Si/Zn — 7798 7023 — — — (molar ratio)Si/Ge — — — — — — Half width (130) plane 0.193 0.176 0.163 0.125 0.1440.147 (510) plane 0.193 0.198 0.171 0.122 0.163 0.139 (A₂/A₁) × 100 (%)51.3 54.6 54.4 50 32 47.5 Average primary particle 150 150 180 750 1602900 diameter(nm) Methanol conversion (%) 96.6 99.4 98.8 100 100 73.7Ethylene selectivity (mol %) 2.5 3.3 3.2 5.2 2.9 1.9 Propyleneselectivity (mol %) 49.3 50.2 48 46.1 54.7 20.7 Butene selectivity (mol%) 26.6 25.3 24.8 17.4 20 13.8 Catalyst life L₁ (hr) 24 26 24 6 20 1Catalyst life L₂ (hr) 36 30≤*¹ 38≤*² 6 22 1 Comparative ComparativeComparative Example 3 Example 4 Example 5 Example 5 Example 6 Initialcharge TMMAOH/Si 0.2 0.2 0.2 0.2 0.2 composition NaOH/Si 0.1 0.08 0.080.1 0.1 (molar ratio) H₂O/Si 30 20 20 30 30 H₃BO₃/Si 0.04 0.04 0.04 0.040.04 (CH₃COO)₂Zn/ — — — — — Si GeO₂/Si — — — — 0.06 Al₂(SO₄)₃/Si 0.00250.007 0.007 — — Seed/Si 0.02 0.02 0.02 0.02 0.02 Post-treatment H₂O/Si —— — 333 333 composition Al(NO₃)₃/Si — — — 0.0025 0.0025 (molar ratio)Zeolite Si/Al 192 84 297 262 246 catalyst Si/B 24 26 n.d. 481 n.d.composition Si/Zn — — — — — (molar ratio) Si/Ge — — — — 721 Half width(130) plane 0.133 0.114 0.111 0.126 0.121 (510) plane 0.141 0.117 0.120.125 0.117 (A₂/A₁) × 100 (%) 38.8 44 48.6 61.6 54.3 Average primaryparticle 360 660 820 570 940 diameter(nm) Methanol conversion (%) 100 9996.7 99.6 99.1 Ethylene selectivity (mol %) 4.2 7 3 3.3 3.3 Propyleneselectivity (mol %) 50.6 48.5 53.9 48.6 46.2 Butene selectivity (mol %)18.4 15.7 19.1 25.7 25.1 Catalyst life L₁ (hr) 12 2 2 28 10 Catalystlife L₂ (hr) 12 2 5 36 18 *¹There is no data after 30 hr, but theconversion at 30 hr is 94.4%. *²There is no data after 38 hr, but theconversion at 38 hr is 92.7%.

When the results of Examples 1 to 3, Example 5 and Comparative Examples1 to 5 in Table 2 are compared, it is obvious that a zeolite, in whichthe ratio with respect to the integrated intensity areas ((A₂/A₁)×100(%)) is large, and the average primary particle diameter is small, has along catalyst life. In the case of the zeolite of Examples 4 and 6, theaverage primary particle diameter is relatively large, and therefore thecatalyst life is short compared to Examples 1 to 3, but the catalystlife is still longer compared to Comparative Examples 4 and 5 havingalmost equivalent average primary particle diameter. In the case ofExample 5, it shows a lifetime comparable to Examples 1 to 3 despite alarge average primary particle diameter. This is conceivably because theratio with respect to the integrated intensity areas ((A₂/A₁)×100 (%))is larger than in Examples 1 to 3. The above means that the catalystlife of a zeolite having a high ratio with respect to the integratedintensity areas ((A₂/A₁)×100 (%)) is long.

Next, other aspects of the present invention will be described.

Other aspects are as the following [1] to [10]. Hereinafter, “thepresent embodiment” refers to an embodiment of the inventions of [1] to[10].

[1] A CON zeolite satisfying the following (1) to (2).

(1) The framework is CON as per the code specified by the InternationalZeolite Association (IZA).

(2) It contains silicon and aluminum, and the molar ratio of aluminum tosilicon is 0.04 or more.

[2] The CON zeolite according to [1] having a crystal of polymorph B.[3] The CON zeolite according to [1] or [2], wherein the molar ratio ofaluminum to silicon is higher than 0.08.[4] A method of producing a zeolite of the type CON as per the codespecified by the International Zeolite Association (IZA) by hydrothermalsynthesis of a mixture containing a silicon source, an aluminum source,an alkali metal element source and/or an alkaline earth metal elementsource, an organic structure-directing agent, and water, wherein themolar ratio of aluminum to silicon in the mixture is higher than 0.01.[5] The method of producing a CON zeolite according to [4], which is amethod of producing a zeolite having a crystal of polymorph B.[6] The method of producing a CON zeolite according to [4] or [5],wherein the molar ratio of aluminum to silicon in the mixture is 0.08 ormore.[7] A CON zeolite obtained by the method of producing a CON zeoliteaccording to any one of [4] to [6].[8] A catalyst for producing a lower olefin or an aromatic hydrocarboncontaining the CON zeolite according to any one of [1] to [3], or [7].[9] An adsorbent containing the CON zeolite according to any one of [1]to [3], or [7].[10] An exhaust gas treatment catalyst containing the CON zeoliteaccording to any one of [1] to [3], or [7].

The present embodiment relates to a method of producing a CON zeolitehaving a high aluminum content, and a CON zeolite, which is produced bythe method, and has higher catalytic performance and stability than thecase where it is synthesized in two stages using a conventional main rawmaterial of boron, as well as a use of the same.

Zeolite has characteristics, such as molecular sieve effect, ionexchange ability, catalytic ability, and adsorption ability due to poresderived from its framework structure, and is currently widely used as anadsorbent, an ion exchanger, an industrial catalyst, and anenvironmental catalyst.

The CON zeolite is one of zeolites having pores of 10-membered oxygenring and two types of 12-membered oxygen rings, and has a topology whichis classified as CON as per the framework code defined by theInternational Zeolite Association (hereinafter occasionally abbreviatedas “IZA”). Since the CON zeolite has large pores of different sizes, itis expected as a catalyst for producing a lower olefin and an aromatic,an adsorbent, and an exhaust gas treatment catalyst.

As a CON zeolite CIT-1 ([B]-CON) and SSZ-33 ([B]-CON) as a borosilicate,SSZ-26 ([Al]-CON) as an aluminosilicate, and ITQ-24 ([Ge]-CON) as agermanosilicate have been known.

CIT-1 is a CON zeolite containing boron as a main component, which iscomposed of a single component of polymorph B. As a general productionmethod, U.S. Pat. No. 5,512,267 discloses a basic method, and as aspecific production method, a zeolite CIT-1 containing boron (Si/B₂ratio=50) is yielded by conducting a hydrothermal synthesis at 175° C.for 7 days using fumed silica and sodium borate as raw materials,N,N,N-trimethyl-cis-myrtanylammonium hydroxide as an organicstructure-directing agent, and NaOH as an alkali source. U.S. Pat. No.5,512,267 claims that synthesis is possible to introduce silicon,germanium, aluminum, gallium, iron, titanium, vanadium, or a mixedcomposition thereof as a T atom, however in fact substantially allExamples were related to [B]-CON containing silicon and boron as maincomponents. In a synthesis of [Al]-CON containing aluminum in Example, atechnique, by which [B]-CON was first synthesized and then aluminum wasintroduced by ion exchange in an aluminum nitrate aqueous solution, wasused.

Am. Chem. Soc. Catal., 5, 4268 (2015), Japanese Unexamined PatentApplication Publication No. 2013-245163 disclose a direct productionmethod by a hydrothermal synthesis of boroaluminosilicate containingboron as well as a small amount of aluminum. Specifically, according tothe disclosure, [B, Al]-CON having a Si/B₂ ratio from 50 to 74 and aSi/Al₂ ratio from 218 to 310 may be produced by using boron as a maincomponent at a Si/B₂ ratio of 50, then adding aluminum sulfate, andperforming a hydrothermal synthesis at a Si/Al₂ ratio from 200 to 400.However, there has been presented data showing that [B, Al]-CON cannotbe produced with a composition of a Si/Al₂ ratio less than 200. Asevidenced by this fact, it is a common technical knowledge which hasbeen established through the 20 year history of CIT-1, that CIT-1 is azeolite which can be synthesized only when boron is a main component.

SSZ-33 is a CON zeolite containing boron as a main component similarlyto CIT-1, however it is an intergrowth of polymorphs A/B (70:30) withdifferent layering modes. The production method is disclosed in U.S.Pat. No. 4,963,337, and it is so described that a borosilicate having aSi/B₂ ratio from 30 to 50 may be synthesized by performing synthesisusing fumed silica and sodium borate as raw materials, and N, N,N-trimethyltricyclo [5.2.1.0^(2,6)] decane ammonium hydroxide as anorganic structure-directing agent. Similarly, to CIT-1, introduction ofaluminum in Example was carried out after yielding a borosilicate byhydrothermal synthesis, by ion exchange in an aluminum nitrate aqueoussolution.

Meanwhile, SSZ-26 is a CON zeolite containing aluminum as a maincomponent, but it is an intergrowth of polymorphs A/B (85:15) withdifferent layering modes. A production method thereof is disclosed inU.S. Pat. No. 4,910,006, and specifically by performing synthesis usingfumed silica, zeolite Y as raw materials, and hexamethyl [4.3.3.0]propellane-8,11-diammonium cation as an organic structure-directingagent, an aluminosilicate having a Si/Al₂ ratio from 25 to 35 isobtained.

Also, ITQ-24 is a CON zeolite containing germanium as a main component,which is composed of a single component of polymorph C with a layeringmode different from CIT-1. A production method thereof is disclosed inJ. Am. Chem. Soc., 125, 7820 (2003), and specifically by performinghydrothermal synthesis at 175° C. for 15 days using tetraethoxysilane,germanium oxide, and aluminum isopropoxide as raw materials, and addinghexamethonium hydroxide as an organic structure-directing agent toobtain [Ge, Al]-CON (Si/Ge₂=10, Si/Al₂=37) containing silicon as well asgermanium as main components.

As mentioned above, examples of a zeolite having a CON framework includeCIT-1, SSZ-26, SSZ-33, and ITQ-24, but they are treated as differentmaterials characterized by the respective XRD patterns, because they aredifferent not only in constituent elements but also in polymorphproperties.

However, the aforedescribed known methods have various drawbacks, andfully satisfactory results have not been obtained.

Since a CON zeolite (CIT-1) containing silicon and boron as maincomponents was produced by the method disclosed in U.S. Pat. No.5,512,267, Japanese Unexamined Patent Application Publication No.2013-245163, and Am. Chem. Soc. Catal., 5, 4268 (2015), in order toyield a CON zeolite with a high aluminum content, it was necessary to gothrough two steps, namely to synthesize borosilicate at first, and thento introduce aluminum by a subsequent post-treatment. Therefore, therewas a drawback in that the production cost became high. Further, therewas an upper limit of the boron content in a borosilicate (Si/B₂ molarratio of about 50), and there was a drawback in that it was not possibleto introduce more aluminum into the framework. In addition, Al insertioninto the zeolite framework may be incomplete, and aluminum speciesoutside the framework tends to increase, and a zeolite, in whichaluminum species is instable, tends to be yielded.

Further, since a CON zeolite (SSZ-33) containing silicon and boron asmain components similar to the aforedescribed CIT-1 was produced by themethod disclosed in U.S. Pat. No. 4,963,337, in order to yield a CONzeolite with a high aluminum content, two production steps of ahydrothermal synthesis step and a post-treatment step were required.Further, there was an upper limit of the introduction amount ofaluminum. In addition, there was a drawback in that an organicstructure-directing agent to be used had a very sophisticated structureand was very expensive, forcing the production cost to become high.Further, there was another drawback in that the crystal structuredefined by the organic structure-directing agent inevitably became amixed crystal of polymorphs A/B.

Since a CON zeolite (SSZ-26) containing silicon and aluminum as maincomponents was produced by the method disclosed in U.S. Pat. No.4,910,006, a CON zeolite having a relatively high aluminum content maybe produced. However, there was a drawback in that the introductionamount of aluminum in terms of the Si/Al₂ ratio was limited to a narrowrange of 25 to 35. Further, similarly to SSZ-33, an organicstructure-directing agent to be used had a very sophisticated structureand was very expensive, and therefore the production cost became high.Further, there was another drawback in that the crystal structuredefined by the organic structure-directing agent inevitably became amixed crystal of polymorphs A/B.

Since a CON zeolite (ITQ-24) containing silicon and germanium as maincomponents was produced by the method disclosed in J. Am. Chem. Soc.,125, 7820 (2003), the introduction amount of aluminum was limited, and alarge amount of germanium species susceptible to hydrolysis wascontained, there was another drawback in that the framework wasinstable.

An object of another aspect of the present invention is to provide amethod of producing a CON zeolite having a high aluminum content in onestep by hydrothermal synthesis, a CON zeolite, which is produced by themethod and has a catalytic performance higher than the conventional CONzeolite, and a catalyst composed of the CON zeolite. In addition, anobject of another aspect of the present invention is to provide a methodof producing a CON zeolite capable of widely and freely adjusting the Alcontent, and further to provide a CON zeolite having an Al/Si ratio of0.04 or higher.

As a result of extensive studies by the inventors of the presentinvention for achieving the objects, it has been found that byregulating the ratio of silicon to aluminum in a raw material mixturefor hydrothermal synthesis within a specific range, a CON zeolite havinga high aluminum content, which has not been present heretofore, may beobtained, and even in high yield; that the CON zeolite produced by thismethod is superior in terms of catalytic activity and adsorptionproperty to an [Al]-CON zeolite, which has introduced aluminum by apost-treatment of a conventional [B]-CON zeolite containing boron as amain component; and that a CON zeolite having any Al/Si ratio, includinga CON zeolite having an Al/Si ratio of 0.04 or higher, may be produced;thereby accomplishing such aspect of the present invention.

By another aspect of the present invention, a CON zeolite having a highaluminum content may be produced by a single step hydrothermal synthesiswithout using an expensive structure-directing agent. Moreover, a CONzeolite having a high aluminum content obtained according to anotheraspect of the present invention is superior in catalytic activity andadsorption property to a conventional CON zeolite synthesized in twosteps using boron as a main raw material, and may be used favorably as acatalyst for producing a lower olefin and an aromatic, an adsorbent, anda catalyst for an exhaust gas treatment, and especially as an adsorbentfor hydrocarbons. Further, by the production method of another aspect ofthe present invention, a CON zeolite having an Al/Si ratio of 0.04 orhigher may be produced, and when this is used as an adsorbent forhydrocarbons, it may function as an adsorbent having superior adsorptionperformance. Further, the Al content of an obtained CON zeolite may beadjusted widely.

Representative modes for implementing another aspect of the presentinvention will be described specifically below. However, other aspectsof the present invention are not limited to the following modes insofaras not departing from the scope and spirit of this invention, andvarious modifications are possible.

Another aspect of the present invention (hereinafter also referred to asthe present embodiment) will be described in detail below.

1. CON Zeolite of the Present Embodiment (Structure)

A zeolite of the present embodiment has a CON framework. Regarding theCON zeolite, it is the same as the first embodiment described above.

Its structure may be characterized by X-ray diffraction data. However,when an actually prepared zeolite is measured, since it has beenaffected by the growth direction of zeolite, the ratios amongconstituent elements, adsorbed substances, presence of defects, dryingcondition, etc., the relative intensity, and the peak position of eachpeak may fluctuate slightly. Therefore, it is not possible to reproduceexactly the same values as the parameters of the CON framework set forthin the IZA specifications, and there is tolerance of about 10%.

With respect to the relative intensity and the peak position of eachpeak of a CON zeolite of the first embodiment, there is also toleranceof about 10%.

A CON zeolite of the present embodiment may have a crystal of polymorphB or may be a single crystal of polymorph B. The crystal of polymorph Bis, for example, a crystal having an interplanar spacing d (A) shown inthe following Tables 3A and 3B (Table 3A: a state including an organicstructure-directing agent, and Table 3B: a state not including anorganic structure-directing agent). With respect to the interplanarspacing, difference of ±0.3° in terms of 2θ and ±2% in terms of eachinterplanar spacing d may be tolerated, from the values in Tables 3A and3B, depending on difference in a production method, etc. The method ofmeasuring an interplanar spacing is as described in Examples below.Among the interplanar spacings in Table 3A, principal interplanarspacings d for identifying CIT-1 which is a crystalline form ofpolymorph B are: 9.86 Å (9.77), 6.26 Å (6.26), 5.84 Å (5.79), 5.67 Å(5.68), 4.91 Å (4.88), 4.54 Å (4.51), 3.73 Å (3.72), and 3.68 Å (3.66)(numerical values in parentheses are values in a state not including anorganic structure-directing agent in Table 3B). For a CON zeolite of thepresent embodiment, at least 6, preferably 7 or more, and morepreferably all of 8 out of 8 spacings are agreed. Further, at least 85%,preferably 90% or more, and more preferably 95% or more of all theinterplanar spacing shown in Tables 3A and 3B are agreed.

There is no particular restriction on the content of polymorph B in aCON zeolite of the present embodiment, and it may be 25% or more, 50% ormore, 75% or more, or 100% on a weight basis.

TABLE 3A Relative Intensity 2θ (°) ^((a)) d (Å) [I/Io × 100] 7.74 11.41Extremely strong 8.35 10.58 Weak 8.96 9.86 Weak 13.14 6.73 Weak 14.146.26 Weak 15.17 5.84 Weak 15.63 5.67 Weak 16.67 5.31 Extremely weak18.04 4.91 Extremely weak 19.56 4.54 Weak 20.20 4.39 Moderate 21.27 4.17Weak 21.90 4.06 Moderate 22.86 3.89 Moderate 23.83 3.73 Weak 24.20 3.68Weak 25.07 3.55 Weak 26.46 3.37 Moderate 27.66 3.22 Extremely weak 27.963.19 Extremely weak 28.59 3.12 Weak 28.90 3.09 Weak 29.59 3.02 Extremelyweak 30.25 2.95 Extremely weak 30.78 2.90 Extremely weak 31.43 2.84Extremely weak 31.84 2.81 Extremely weak 33.13 2.70 Extremely weak 35.252.54 Extremely weak 35.65 2.52 Extremely weak 36.82 2.44 Extremely weak37.17 2.42 Extremely weak ^((a)) (±0.3)

TABLE 3B Relative Intensity 2θ (°) ^((a)) d (Å) [I/Io × 100] 7.77 11.36Extremely strong 8.35 10.58 Weak 9.04 9.77 Weak 13.19 6.71 Weak 14.146.26 Weak 15.30 5.79 Extremely weak 15.60 5.68 Extremely weak 16.70 5.30Extremely weak 18.16 4.88 Extremely weak 19.69 4.51 Extremely weak 20.254.38 Weak 21.37 4.15 Weak 21.95 4.05 Weak 23.07 3.85 Moderate 23.93 3.72Extremely weak 24.32 3.66 Extremely weak 25.25 3.52 Weak 26.52 3.36 Weak27.73 3.22 Extremely weak 28.53 3.13 Extremely weak 28.93 3.08 Weak29.64 3.01 Extremely weak 30.45 2.93 Extremely weak 31.51 2.84 Extremelyweak 33.32 2.69 Extremely weak 35.45 2.53 Extremely weak 35.71 2.51Extremely weak 36.90 2.43 Extremely weak ^((a)) (±0.3)

In this regard, the relationship between the XRD relative intensity inabove Tables and the value of an XRD peak expressed by I/Io×100 in theactual XRD pattern is as shown in the following Table 3C below. InTables 3A and 3B above, I and I₀ have the following meanings:

I: X-ray diffraction intensity at each interplanar spacing d

I₀: The maximum XRD peak intensity in the XRD pattern

TABLE 3C XRD Relative Intensity relative intensity [I/I₀ × 100]Extremely strong not less than 90 Strong not less than 70 and less than90 Moderate not less than 30 and less than 70 Weak not less than 10 andless than 30 Extremely weak less than 10

(Constituent Component)

A CON zeolite of the present embodiment contains aluminum as a componentother than silicon and oxygen, and contains 90 mol % or more of siliconatoms and aluminum atoms in the T atoms. In addition, at least oneelement M selected from boron, gallium, and iron (hereinafter simplyreferred to as “element M”) may be contained in the T atoms.

Since a zeolite of the present embodiment includes aluminum as a maincomponent in addition to silicon in the T atoms, it develops an activesite with a high acid strength and functions as an active site for aconversion reaction of methanol or a hydrocarbon. Therefore, it issuperior in catalytic performance. When it is used as an adsorbent for ahydrocarbon, etc., it is preferable that the content of aluminum ishigh, because the adsorption capacity may be larger, and the desorptiontemperature tends to be higher. Also, when it is used as an SCR catalystfor a treatment of an exhaust gas of an automobile, etc., a catalystwith a higher aluminum content is superior in the efficiency of exhaustgas treatment especially during an operation at a low temperature at thestart.

As a zeolite of the present embodiment, an aluminosilicate, in which theT atoms are composed of silicon and aluminum, a boroaluminosilicate, agalloaluminosilicate, a ferrialuminosilicate, aborogalloaluminosilicate, and a boroferrialuminosilicate are preferable;an aluminosilicate, a boroaluminosilicate, and a ferrialuminosilicateare more preferable; and an aluminosilicate, in which the T atoms arecomposed of silicon and aluminum, and a boroaluminosilicate composed ofsilicon, aluminum and boron are further preferable.

A zeolite of the present embodiment may contain additional elementsother than the above elements. Examples of other elements include, butnot limited to, zinc (Zn), germanium (Ge), titanium (Ti), zirconium(Zr), and tin (Sn). These constituent elements may be used singly, or ina combination of two or more types.

(Molar Ratio of Aluminum to Silicon)

The molar ratio (Al/Si) of aluminum to silicon in a zeolite of thepresent embodiment is usually 0.01 or more, preferably 0.02 or more,more preferably 0.04 or more, further preferably 0.05 or more, andespecially preferably higher than 0.08; and is usually 0.30 or less,preferably 0.20 or less, more preferably 0.15 or less, furtherpreferably 0.13 or less, and especially preferably 0.10 or less. Whenthe Al/Si molar ratio falls within the above range, a sufficientquantity of acid sites having a high acid strength may be obtained, andin a conversion reaction of an organic compound raw material, a highadsorption ability for an organic compound, a high conversion activity,and olefin interconversion activity are obtained. Further, it ispossible to prevent phenomena, such as deactivation of the catalyst bycoking, desorption of T atoms other than silicon from the framework, anddecrease in acid strength per acid site. Also, in a case in which thezeolite is used as an adsorbent, when the Al/Si molar ratio is withinthe above range, the number of adsorption sites derived from Alincreases so that a high adsorption ability is obtained. Furthermore,due to the high adsorption ability, the desorption temperature becomeshigher, and desorption at a low temperature may be suppressed. Forexample, in a case in which the zeolite is used as an adsorbent for ahydrocarbon, etc., especially as an adsorbent for adsorbing hydrocarbonsemitted from an automobile engine (a hydrocarbon trapping material), thesame is able to adsorb and retain a large amount of emitted hydrocarboncomponents during a cold start of an internal combustion engine (in alow temperature period). Also, in a case in which the zeolite is used asan SCR catalyst, when the Al/Si molar ratio is within the above range,it has advantageously a high purification performance on an exhaust gascontaining nitrogen oxides owing to a large number of active sites as acatalyst. For example, in a truck, since it is used as an SCR catalystin an atmosphere of a gas containing water vapor at a relatively lowtemperature of 700° C. or less, removal of Al from the framework by awater vapor hardly proceeds. As a result, the purification performanceof an exhaust gas containing nitrogen oxides is given priority, and useof a zeolite having a large number of active sites in the zeoliteframework, namely a zeolite having a high Al/Si molar ratio is desired.On the other hand, a zeolite having a small Al/Si molar ratio has anadvantage in that the structure is not easily collapsed even in a hightemperature gas atmosphere containing water vapor because the amount ofAl in the zeolite framework is small. In the case of a diesel passengercar or a gasoline-powered car, since the zeolite is used as an SCRcatalyst in an atmosphere of a gas containing water vapor at 800° C. orhigher, high steam resistance is required. Therefore, it is desirable touse a zeolite having a small Al/Si molar ratio. In this regard, a CONzeolite having an Al/Si molar ratio of 0.04 or more has never beenobtained in the past, and the same is a novel material. Considering allthe foregoing together, the Al/Si molar ratio is preferably from 0.04 to0.13, and more preferably from 0.05 to 0.10 for suppressing the effectof elimination of Al from the framework, and obtaining a high catalyticperformance and an adsorption performance for a conversion reaction ofan organic compound raw material, an adsorbent, and an exhaust gastreatment catalyst.

(Molar Ratio of Boron to Silicon)

The molar ratio (B/Si) of boron to silicon in a zeolite of the presentembodiment is usually 0 or more, preferably 0.00002 or more, morepreferably 0.0002 or more, further preferably 0.0004 or more, andespecially preferably 0.0008 or more; and is usually 0.04 or less,preferably 0.02 or less, more preferably 0.008 or less, furtherpreferably 0.004 or less, and especially preferably 0.002 or less. Sincealuminum is generally less apt to be eliminated from the framework thanboron, when the B/Si molar ratio falls within the above range, it ispreferable that the B/Si molar ratio is low, namely that the boroncontent is relatively reduced, because the structural destruction due toelimination from the framework may be suppressed.

(Molar Ratio of Boron to Aluminum)

There is no particular restriction on the content of boron in thecrystals of a zeolite of the present embodiment, and it is preferablylow, namely the molar ratio of boron to aluminum (B/Al) is usually 1.0or less, preferably 0.2 or less, more preferably 0.02 or less, furtherpreferably 0.002 or less, and especially preferably 0.0002 or less. Ingeneral aluminum is less apt to be eliminated from the framework thanboron, therefore it is preferable that the B/Al molar ratio is low,namely that the boron content is relatively reduced, because thestructural destruction due to elimination from the framework may besuppressed.

The contents of Si, Al, and M (B, Fe, and Ga) in a zeolite of thepresent embodiment may be measured usually by ICP elemental analysis orfluorescent X-ray analysis. In the fluorescent X-ray analysis, acalibration curve is prepared between the fluorescent X-ray intensity ofa test element in a reference sample and the atomic concentration of thetest element, and the contents of silicon atoms, aluminum, gallium, andiron atoms in a zeolite sample may be determined by the X-rayfluorescence analysis (XRF) using the calibration curve. However, sincethe intensity of the fluorescent X-ray of the boron element isrelatively weak, it is preferable to measure the content of the boronatom by an ICP element analysis.

(Fluorine Content)

Although there is no particular restriction on the content of fluorinein the crystal of a zeolite of the present embodiment, it is preferablyas low as possible, usually 5000 ppm or less, preferably 1000 ppm orless, more preferably 100 ppm or less, and most preferably 0 ppm. Byadjusting the fluorine content in the zeolite crystal within the aboverange, a sufficient specific surface area may be obtained, further, highdiffusivity of a hydrocarbon component in the crystal may be obtained,and the conversion activity for an organic compound raw material may beenhanced.

(Total Acid Content)

The total acid content of a zeolite of the present embodiment(hereinafter referred to as “total acid content”) is a sum total of thenumber of acid sites present in pores of the crystal of the zeolite andthe number of acid sites on the outer surface of the crystal of thezeolite (hereinafter referred to as the outer surface acid content).Although there is no particular restriction on the total acid content,it is usually 0.10 mmol/g or more, preferably 0.30 mmol/g or more, morepreferably 0.40 mmol/g or more, further preferably 0.50 mmol/g or more,and especially preferably 0.60 mmol/g or more. Also, it is usually 1.5mmol/g or less, preferably 1.2 mmol/g or less, more preferably 1.0mmol/g or less, further preferably 0.90 mmol/g or less, and especiallypreferably 0.80 mmol/g or less. By adjusting the total acid contentwithin the above range, the conversion activity of an organic compoundraw material may be secured, and coking generation of coke inside poresof a zeolite is inhibited so that the diffusibility of a molecule in thecrystal may be maintained, which is preferable. In a case in which thezeolite is used as an adsorbent, when the total acid content is withinthe above range, the number of adsorption sites increases, so that ahigh adsorption ability may be obtained. Also, in a case in which thesame is used as an SCR catalyst, the number of catalytic active siteincreases, so that it has advantageously high purification performancefor an exhaust gas containing nitrogen oxides.

In this regard, the total acid content may be calculated from thedesorbed amount in ammonia temperature-programmed desorption (NH₃-TPD).Specifically, a zeolite is dried in vacuum at 500° C. for 30 min as apretreatment, and then the pre-treated zeolite is brought into contactwith an excess amount of ammonia at 100° C. to adsorb ammonia thereon.The obtained zeolite is dried in vacuum at 100° C. (or brought intocontact with steam at 100° C.) to remove excessive ammonia from thezeolite. Next, the zeolite having adsorbed ammonia is heated in a heliumatmosphere at a temperature elevation rate of 10° C./min, and thedesorbed amount of ammonia is measured by mass spectrometry from 100° C.to 600° C. The desorption amount of ammonia per weight of zeolite isdeemed as the total acid content. However, the total acid content in thepresent embodiment is defined as the sum of the areas of the waveformshaving its peak top at 240° C. or higher after waveform separation ofthe TPD profile by Gaussian functions. The “240° C.” is an index usedonly for judgment of the position of a peak top, but not for calculatingonly the area of the portion of 240° C. or higher. Insofar as a waveformhas its peak top at 240° C. or higher, the “waveform area” means thetotal area including the portion not higher than 240° C. In the casewhere there are a plurality of waveforms having a peak top at 240° C. orhigher, the respective areas are summed up.

The total acid content according to the present embodiment does notinclude the acid content derived from a weak acid site having a peak topbelow 240° C. This is because it is not easy to distinguish betweenadsorption derived from a weak acid site and physical adsorption in theTPD profile.

(Outer Surface Acid Content)

Although there is no particular restriction on the acid content on thecrystal outer surface of a zeolite of the present embodiment, it isusually 10% or less with respect to the total acid content of thezeolite, preferably 8% or less, and more preferably 5% or less. When theacid content on the outer surface is too high, it becomes difficult toobtain the shape selectivity unique to zeolite pores due to a sidereaction occurring at the acid site on the outer surface, and theselectivity tends to decrease. There is no particular restriction on amethod for adjusting the acid content on the outer surface of thezeolite, and examples thereof include silylation, steam treatment, andheat treatment of the outer surface of the zeolite. Further, there is amethod, by which a binder and the acid site on the outer surface of thezeolite are bonded together in forming the zeolite.

An acid content on the outer surface may be calculated from the amountof a probe molecule (desorbed amount) per catalyst weight, when a probemolecule, which is too large to enter the pores of a zeolite, such as4-propylquinoline, and 4-butylquinoline, is made to be adsorbed to anacid site on the zeolite surface, and then the adsorbed molecule is madeto be desorbed from the catalyst by temperature increase. Specifically,for an acid content on the outer surface, a zeolite is dried at 500° C.in vacuum for 1 hour in a pre-treatment, then brought in contact with avapor of probe molecules under a reduced pressure condition at 200° C.to 240° C., and an excessive amount of probe molecules is removed byevacuation and purging with helium at 200° C. to 240° C., the obtainedzeolite is heated in a helium atmosphere at a temperature elevation rateof 10° C./min, and the desorbed amount of the probe molecules from 100°C. to 600° C. is measured by mass spectrometry. However, the acidcontent on the outer surface according to the present embodiment isdefined similarly to the total acid content, as the sum of the areas ofthe waveforms having its peak top at 240° C. or higher after waveformseparation of the TPD profile by Gaussian functions.

(Ion Exchange Site)

There is no particular restriction on the ion exchange site of a zeoliteof the present embodiment. Usually, it is a proton (hereinafter alsoreferred to as “protonic” or “H type”) or partly a metal ion of analkali metal such as lithium (Li), sodium (Na), potassium (K), andcesium (Cs); an alkaline earth metal such as magnesium (Mg), calcium(Ca), strontium (Sr), and barium (Ba); or the like. The ion exchangesite is preferably a proton, sodium, potassium, or calcium, morepreferably proton, sodium, and potassium, further preferably proton, andsodium, and especially preferably proton from the viewpoint ofimprovement of molecular diffusivity by decreasing the space occupied bya metal in the pore space. Hereinafter, for example, that exchanged witha Na ion is sometimes referred to as “Na type”. That ion-exchanged withan ammonium (NH₄) is usually treated equivalently as a protonic type,because ammonia is eliminated therefrom under reaction conditions at ahigh temperature.

(Content of Alkali Metal/Alkaline Earth Metal)

Although there is no particular restriction on the total content of analkali metal and an alkaline earth metal in a zeolite of the presentembodiment, it is usually 0.005 mass % or more, preferably 0.01 mass %or more, more preferably 0.1% mass % or more, and further preferably 0.5mass % or more; and is usually 10 mass % or less, preferably 5 mass % orless, more preferably 3 mass % or less, and further preferably 1 mass %or less. By adjusting the total content of an alkali metal and analkaline earth metal within the above range, the acid content, or thepore-space volume of a zeolite may be adjusted, so that accumulation ofcoke during the reaction may be advantageously suppressed. Further, thethermal/hydrothermal stability is improved, and deterioration may besuppressed, which is also advantageous.

(Average Primary Particle Diameter)

Although there is no particular restriction on the average primaryparticle diameter of a zeolite of the present embodiment, it is usually0.03 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm ormore, further preferably 0.15 μm or more, and especially preferably 0.20μm or more; and is usually 5 μm or less, preferably 2 μm or less, morepreferably 1 μm or less, further preferably 0.60 μm or less, andespecially preferably 0.40 μm or less. By adjusting the primary particlediameter within the above range, the diffusibility in a zeolite crystalduring a catalytic reaction and the effectiveness factor of catalyst maybe sufficiently high, the zeolite crystallinity may be sufficient, andthe hydrothermal stability may be high, which is preferable.

An average primary particle diameter in the present embodimentcorresponds to the particle diameter of the smallest particle whichgrain boundary is not recognizable. Therefore, it is different from theparticle diameter of an aggregate to be measured by the light scatteringmethod, or the like. An average particle diameter is determined bymeasuring optional 50 or more particles through observation with ascanning electron microscope (hereinafter abbreviated as “SEM”), or atransmission electron microscope (hereinafter abbreviated as “TEM”), andaveraging the particle diameters of the primary particles. The particlediameter was defined as the diameter (equivalent circle diameter) of acircle having an area equal to the projected area of the particle.

In this regard, it is not necessary for primary particles to be presentas independent particles in the present embodiment, and they may form asecondary particle by aggregation or otherwise. Even if a secondaryparticle is formed, it is possible to distinguish primary particles onthe surface of a secondary particle in the SEM or TEM image.

(BET Specific Surface Area)

Although there is no particular restriction on the BET specific surfacearea of a zeolite of the present embodiment, it is usually 300 m²/g ormore, preferably 400 m²/g or more, and more preferably 500 m²/g or more;and is usually 1000 m²/g or less, preferably 800 m²/g or less, and morepreferably 750 m²/g or less. Within the above range, the number ofactive sites present on the inner surfaces of pores is sufficientlylarge so that the catalytic activity may be enhanced advantageously. ABET specific surface area may be measured by a measuring methodaccording to JIS 8830 (Determination of the specific surface area ofpowders (solids) by gas adsorption). A BET specific surface area may beobtained by the one point method (relative pressure: p/p₀=0.30) usingnitrogen as the adsorption gas.

(Pore Volume)

Although there is no particular restriction on the pore volume of thezeolite of the present embodiment is not particularly limited, it isusually 0.10 mL/g or more, preferably 0.15 mL/g or more, and morepreferably 0.20 mL/g or more; and is usually 0.50 mL/g or less,preferably 0.40 mL/g or less, and more preferably 0.35 mL/g or less.Within the above range, the number of active sites present on the innersurfaces of pores is sufficiently large so as to promote adsorption of ahydrocarbon component and to enhance advantageously the catalyticactivity. The pore volume is preferably a value determined from theadsorption isotherm of nitrogen obtained by the relative pressuremethod.

(²⁹Si-NMR)

The fact that the CON zeolite of the present embodiment is superior incrystallinity is also indicated by that the difference between theSi/Al₂ ratio of the bulk and the Si/Al₂ ratio obtained by ²⁹Si-NMR aftercalcination is small. In other words, the Si/Al₂ ratio obtained by anelemental analysis of the calcined CON zeolite is the Si/Al₂ ratio ofthe bulk containing silicon and aluminum in the portion where theframework is broken during hydrothermal synthesis or calcination,meanwhile, the Si/Al₂ ratio determined by ²⁹Si-NMR after calcination isthe ratio of silicon to aluminum that are retained in the zeoliteframework even after calcination. Since aluminum elimination occurs moreeasily, the ²⁹Si-NMR (Si/Al₂ ratio)/XRF (Si/Al₂ ratio) in terms of %tends to be 100% or higher. In particular, in the case of a CON zeolitein which Al is introduced into the framework in two stages by apost-treatment after hydrothermal synthesis, the amount of aluminum ofthe bulk increases, however uptake into the framework itself is limited,and Al is present outside the framework in a large amount.

On the other hand, since a CON zeolite of the present embodiment hasgood crystallinity despite a low Si/Al₂ ratio, elimination of Al is notapt to occur even by calcination. This is a characteristic that leads tohigh durability in use, which is a favorable characteristic when thezeolite is used as a catalyst. Specifically, the ratio of the Si/Al₂ratio of a zeolite after calcination obtained by ²⁹Si-NMR to the Si/Al₂ratio of the bulk, which may be expressed by [²⁹Si-NMR (Si/Al₂ratio)/elemental analysis (Si/Al₂ ratio)], is in terms of % preferably80% or more, more preferably 90% or more, and further preferably 100% ormore; and is preferably 200% or less, more preferably 180% or less,further preferably 160 mass % or less, and especially preferably 140mass % or less.

(²⁷Al-NMR)

In general, aluminum (Al) in a zeolite crystal is mostly atetracoordinated Aluminum (hereinafter referred to as “tetracoordinatedAl”) incorporated into the framework, or a hexacoordinated aluminum(hereinafter referred to as “hexacoordinated Al”) existing outside theframework. When the amount of the tetracoordinated Al is large, thenumber of Bronsted acid sites is also large. For this reason, it ispreferable that a CON zeolite of the present embodiment contains moretetracoordinated Al. In a CON zeolite of the present embodiment, thepercentage of tetracoordinated Al with respect to the total oftetracoordinated Al and hexacoordinated Al (hereinafter referred to as“tetracoordinated Al rate”) is usually 70% or more, preferably 80% ormore, more preferably 90% or more, and further preferably 95% or more.Since the tetracoordinated Al rate is the percentage of tetracoordinatedAl in aluminum in the crystal, its value is 100%, or less. Thetetracoordinated Al rate is a value obtained from the following formula.

Tetracoordinated Al rate (%)=[Tetracoordinated Al/(TetracoordinatedAl+Hexacoordinated Al)]×100

In the above formula, Tetracoordinated Al is the area of the peak havingthe peak top at 55±5 ppm in ²⁷Al-NMR and Hexacoordinated Al is the areaof the peak having the peak top at 0±5 ppm in ²⁷Al-NMR.

2. Method of Producing CON Zeolite

A method of producing a CON zeolite of the present embodiment compriseshydrothermal synthesis using a mixture which contains a silicon source,an aluminum source, an alkali metal source and/or an alkaline earthmetal source, an organic structure-directing agent and water, andproduces the CON zeolite which has the molar ratio of aluminum tosilicon higher than 0.01, and which is coded as CON according to thespecifications of the International Zeolite Association (IZA). It ispreferable to produce a zeolite having a crystal of polymorph B.

A CON zeolite of the present embodiment may be produced by commonprocedures for hydrothermal synthesis of zeolite except for the abovecharacteristics. Namely, the zeolite may be synthesized by a method inwhich a crystal precursor mixture including a silicon source, analuminum source, an alkali metal element source and/or an alkaline earthmetal element source, an organic structure-directing agent, water, andif necessary, a seed crystal is prepared, and subjected to hydrothermalsynthesis.

An example of a production method will be described below.

(Components of Mixture) (a) Silicon Source

There is no particular restriction on the silicon source used in thepresent embodiment, and examples thereof include a silicate, such asfine powdered silica, silica sol, silica gel, silicon dioxide, and waterglass, an alkoxide of silicon, such as tetramethoxysilane andtetraethoxysilane, and a halide of silicon. Further, a silica-containingzeolite, such as FAU zeolite, and CHA zeolite, andsilicoaluminophosphate may be used as a silicon source.

These silicon sources may be used singly, or in a combination of two ormore kinds thereof.

Among these silicon sources, fine powdered silica, silica sol, waterglass, silica-containing zeolite, and the like are preferably used fromthe viewpoint of cost advantages and ease of handling, and morepreferably silica sol, water glass, and silica-containing zeolite areused from the viewpoint of reactivity.

(b) Aluminum Source

There is no particular restriction on the aluminum source used in thepresent embodiment, and examples thereof include amorphous aluminumhydroxide, aluminum hydroxide having a gibbsite structure, aluminumhydroxide having a bayerite structure, aluminum nitrate, aluminumsulfate, aluminum oxide, sodium aluminate, boehmite, pseudoboehmite,alumina sol, and an aluminum alkoxide. Further, an aluminum-containingzeolite, such as FAU zeolite, and CHA zeolite, or aluminophosphate maybe used as an aluminum source.

These aluminum sources may be used singly, or in a combination of two ormore kinds thereof.

Among these aluminum sources, amorphous aluminum hydroxide, aluminumhydroxide having a gibbsite structure, aluminum hydroxide having abayerite structure, and an aluminum-containing zeolite are usedpreferably from the viewpoint of cost advantages and ease of handling,and amorphous aluminum hydroxide, and an aluminum-containing zeolite areused more preferably from the viewpoint of reactivity.

(c) Alkali Metal Element Source and/or Alkaline Earth Metal ElementSource

There is no particular restriction on an alkali metal element and analkaline earth metal element included in the mixture to be subjected tohydrothermal synthesis according to the present embodiment, and examplesthereof include lithium, sodium, potassium, rubidium, cesium, beryllium,magnesium, calcium, strontium, and barium. Although these may beincluded singly, or two or more of them may be included, it ispreferable that an alkali metal element is included in view of highalkalinity, and easy crystallization of zeolite especially when asoluble raw material is used.

Examples of an alkali metal element source, and an alkaline earth metalelement source include a hydroxide, a chloride, a bromide, an iodide, ahydrogencarbonate, and a carbonate thereof. Among these compounds, thehydroxide, the hydrogencarbonate, and the carbonate are basic in anaqueous solution state. Specific examples thereof include a hydroxide,such as lithium hydroxide, sodium hydroxide, potassium hydroxide, cesiumhydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide;a hydrogencarbonate, such as lithium hydrogencarbonate, sodiumhydrogencarbonate, potassium hydrogencarbonate, cesiumhydrogencarbonate, calcium hydrogencarbonate, strontiumhydrogencarbonate, and barium hydrogencarbonate; a carbonate, such aslithium carbonate, sodium carbonate, potassium carbonate, cesiumcarbonate, calcium carbonate, strontium carbonate, and barium carbonate.Among them, a hydroxide of an alkali Metal, such as lithium hydroxide,sodium hydroxide, potassium hydroxide, and cesium hydroxide, ispreferable from the viewpoint of high alkalinity and a promoting effecton dissolution of a raw material and subsequent crystallization ofzeolite; sodium hydroxide, potassium hydroxide, and cesium hydroxide aremore preferable; and sodium hydroxide, and potassium hydroxide arefurther preferable.

These alkali metal sources and alkaline earth metal sources may be usedsingly, or in a combination of two or more kinds thereof.

(d) Organic Structure-Directing Agent

As an organic structure-directing agent (also called as “template”; anorganic structure-directing agent is hereinafter occasionally referredto as “SDA”), a publicly known substance, such as tetraethylammoniumcation (TEA), and tetrapropylammonium cation (TPA) may be used. Also, asa nitrogen-containing organic structure-directing agent, for exampledescribed in U.S. Pat. No. 5,512,267,N,N,N-trimethyl-(−)-cis-myrtanylammonium cation may be used. Inaddition, it may contain N,N,N-trimethyl-(+)-cis-myrtanylammoniumcation, hexamethonium cation, pentaethonium cation,trimethylbenzylammonium cation, and the like.

Further, as a phosphorus-containing organic structure-directing agent,various known substances, such as tetraethylphosphonium,tetrapropylphosphonium, tetrabutylphosphonium, anddiphenyldimethylphosphonium, may be used.

However, since a phosphorus compound may generate harmful diphosphoruspentoxide in calcination of the synthesized zeolite to remove SDA, it ispreferable to use a nitrogen-containing organic structure-directingagent.

The above ammonium cation, or phosphonium cation accompanies an anion,which does not inhibit formation of a CON zeolite of the presentembodiment. Although there is no particular restriction on the anion,specific examples thereof include a halogen ion, such as Cl⁻, Br⁻, andI⁻, a hydroxide ion, an acetate, a sulfate, and a carboxylate. Amongthese, a hydroxide ion is used especially preferably.

The organic structure-directing agents may be used singly, or in acombination of two or more kinds thereof.

(e) Water

Usually, ion exchanged water is used.

(f) Seed Crystal

A seed crystal may be added to the mixture to be subjected tohydrothermal synthesis according to the present embodiment. As the seedcrystal, a zeolite containing in the framework one of bea, bre, lau, andmel, which are defined as composite building units by the InternationalZeolite Association (IZA), is preferable. Specific examples thereofinclude *BEA type, CON type, IFR type, MSE type, STT type, BOG type, BREtype, HEU type, IWR type, IWW type, RRO type, STI type, TER type, ASVtype, ATO type, BCT type, DFO type, EZT type, ITH type, LAU type, MSOtype, OSI type, -RON type, SAO type, TUN type, UOZ type, DON type, MELtype, MFI type, MWW type, and SFG type; and *BEA type, CON type, IFRtype, MSE type, and STT type are more preferable; *BEA type, CON type,and MSE type are further preferable; and CON type is especiallypreferable.

Examples of the CON zeolite include, but not limited to, B—CONcontaining boron, Al-CON including aluminum, B,Al-CON containing boronand aluminum, B,Fe-CON containing boron and iron, B, Ga—CON containingboron and gallium, Ge—CON containing germanium, Ge,B-CON containinggermanium and boron, and Ge,Al-CON containing germanium and aluminum.Preferable are B-CON, B,Al-CON, and Al-CON; more preferable are B-CON,and B,Al-CON; and further preferable is B,Al-CON. Use of a CON zeolitecontaining boron and/or aluminum in the framework is preferable, becausecrystallization occurs efficiently.

Only one kind of seed crystal may be used, or a combination of thosehaving different structures or compositions may be also used. There isno particular restriction on the composition of a zeolite used as a seedcrystal, insofar as it does not greatly affect the composition of themixture.

Although there is no particular restriction on the particle diameter ofa zeolite to be used as a seed crystal, it is usually 0.03 μm or more asan average primary particle diameter, preferably 0.05 μm or more, morepreferably 0.1 μm or more, and further preferably 0.2 μm or more; andusually 5 μm or less, preferably 2 μm or less, more preferably 1 μm orless, and further preferably 0.60 μm or less. By adjusting the averageprimary particle diameter of a seed crystal within the above range, thesolubility of the seed crystal in the mixture is increased, formation ofa by-product is suppressed, and crystallization of a CON type phase maybe promoted efficiently.

As a seed crystal, either of a zeolite containing a structure-directingagent having not undergone calcination after hydrothermal synthesis, anda calcined zeolite not containing a structure-directing agent may beused. For the sake of effective functioning as a crystal nucleus, it ispreferable to use a zeolite containing structure-directing agent,because a seed crystal should preferably not dissolve too much at theinitial stage of crystallization. However, the solubility of a zeolitecontaining a structure-directing agent may not be sufficient under acondition of low alkali concentration, a condition of low synthesistemperature, or the like. In such a case, it is preferable to use azeolite that does not contain a structure-directing agent.

A seed crystal may be added to the mixture in a form of a dispersion ina suitable solvent such as water, or added as it is without beingdispersed.

(g) The Other Element M Source

A CON zeolite in the present embodiment may contain at least one elementM selected out of boron, gallium, and iron (hereinafter simply referredto as “element M”), in addition to silicon, oxygen, aluminum, alkalimetal elements, and alkaline earth metal elements as constituentelements.

The mixture used in hydrothermal synthesis may contain an element Msource. There is no particular restriction on the element M source, andit may be selected from, for example, a sulfate, a nitrate, a hydroxide,an oxide, an alkoxide of the elements, and an element M-containingzeolite.

Among the element M sources, from the viewpoint of reactivity, asulfate, a nitrate, a hydroxide, and an alkoxide are preferable, andfrom the viewpoint of cost and workability a sulfate, a nitrate, and ahydroxide are more preferable.

As a boron source, boric acid, sodium borate, boron oxide, aboron-containing zeolite, etc. are usually used; preferable are boricacid and sodium borate; and more preferable is boric acid.

As a gallium source, gallium sulfate, gallium nitrate, gallium oxide,gallium chloride, gallium phosphate, gallium hydroxide, agallium-containing zeolite, etc. are usually used; preferable aregallium sulfate and gallium nitrate; and more preferable is galliumsulfate.

As an iron source, iron nitrate, iron sulfate, iron oxide, ironchloride, iron hydroxide, an iron-containing zeolite, etc. are usuallyused; preferable are iron sulfate and iron nitrate; and more preferableis iron sulfate.

The element M sources may be used singly, a combination of two or moreof the same element may be used, or one with different elements, or acombination of two or more with different elements may be used.

Also, the mixture may contain a source of another metal (lead,germanium, titanium, zirconium, tin, chromium, cobalt, etc.). Thesources may be contained singly, or two or more may be included in themixture.

(Composition of Mixture)

A preferred composition of the mixture (slurry or gel) to be subjectedto hydrothermal synthesis in the present embodiment is as follows.

In a case in which a seed crystal is added, the following compositionsare values calculated excluding silicon, aluminum, an element M, analkali metal element, an alkaline earth metal, a structure-directingagent, and water (adsorbed water) contained in a seed crystal.

Although there is no particular restriction on the molar ratio (Al/Si)of the aluminum atom to the silicon atom in the mixture, it is usuallymore than 0.01, preferably 0.015 or more, more preferably 0.02 or more,further preferably 0.04 or more, especially preferably 0.06 or more, andmost preferably 0.08 or more; and is usually 0.30 or less, preferably0.20 or less, more preferably 0.15 or less, further preferably 0.12 orless, and especially preferably 0.10 or less. When the molar ratio ofaluminum atom to silicon atom is within the above range, the CON type isprone to be formed, and the synthesis yield is improved. Further, whenthe product is used as a catalyst, an organic compound material may beefficiently converted by an acid site derived from Al, which ispreferable.

Although there is no particular restriction on the molar ratio of thesum of an alkali metal atom and an alkaline earth metal atom to thesilicon atom [(alkali metal atom+alkaline earth metal atom)/Si] in themixture metal, it is usually 0 or more, preferably 0.10 or more, morepreferably 0.20 or more, further preferably 0.25 or more, and especiallypreferably 0.30 or more; and is usually 0.60 or less, preferably 0.50 orless, more preferably 0.45 or less, further preferably 0.40 or less, andespecially preferably 0.35 or less. By adjusting the ratio within theabove range, incorporation of aluminum into the CON zeolite frameworkbecomes sufficient, and the synthesis yield is improved. Also, formationof a by-product may be suppressed, and the crystallization rate to theCON phase may be favorably accelerated.

Although there is no particular restriction on the molar ratio of thesum of the alkali metal atom and the alkaline earth metal atom to thealuminum atom [(alkali metal atom+alkaline earth metal atom)/Al] in themixture, it is usually 1 or more, preferably 2 or more, more preferably3 or more, and further preferably 4 or more; and is usually 20 or less,preferably 15 or less, more preferably 10 or less, and furtherpreferably 7 or less. By adjusting the ratio within the above range,interaction between the alkali metal and alkaline earth metal, andaluminum during crystallization becomes effective, so that CON zeoliteis likely to be obtained, which is preferable.

Although there is no particular restriction on the content of an organicstructure-directing agent in the mixture, the molar ratio of astructure-directing agent to the silicon atom (organicstructure-directing agent/Si) is usually 0.01 or more, preferably 0.02or more, more preferably 0.05 or more, further preferably 0.10 or more,and especially preferably 0.15 or more; and is usually 0.60 or less,preferably 0.50 or less, more preferably 0.40 or less, furtherpreferably 0.30 or less, and especially preferably 0.25 or less. Byadjusting an organic structure-directing agent in the mixture within theabove range, nucleation in the mixture is promoted, so thatcrystallization of a CON zeolite is promoted, and synthesis in highyield may be achieved, which is preferable. In addition, the amount ofan expensive organic structure-directing agent to be used may besuppressed, and the production cost of zeolite may be reduced, which isalso preferable.

Although there is no particular restriction on the molar ratio of thesum of the organic structure-directing agent, the alkali metal atom, andthe alkaline earth metal atom to the aluminum atom [(organicstructure-directing agent+alkali metal atom+alkaline earth metalatom)/Al] in the mixture metal, it is usually 1 or more, preferably 3 ormore, more preferably 5 or more, and further preferably 6 or more; andis usually 50 or less, preferably 30 or less, more preferably 20 orless, and further preferably 10 or less. By adjusting the ratio withinthe above range, interaction between aluminum and an organicstructure-directing agent, an alkali metal, and an alkaline earth metalduring crystallization becomes effective, so that a CON zeolite iseasily obtained, which is preferable.

It is preferable that N,N,N-trimethyl-(−)-cis-myrtanylammonium cation isincluded in the organic structure-directing agent in the mixture.Although there is no particular restriction on the molar ratio ofN,N,N-trimethyl-(−)-cis-myrtanylammonium cation (hereinafter referred toas “TMMA”) to the total organic structure-directing agents [TMMA organicstructure-directing agents (TMMA+others)], it is usually 0 or more,preferably 0.20 or more, more preferably 0.40 or more, furtherpreferably 0.60 or more, especially preferably 0.80 or more, and theupper limit is 1.0. The higher ratio of TMMA is preferable becausecrystallization of the CON framework proceeds easily.

Although there is no particular restriction on the content of water inthe mixture, the molar ratio of H₂O to silicon (H₂O/Si) is usually 5 ormore, preferably 7 or more, more preferably 9 or more, and furtherpreferably 10 or more; and is usually 50 or less, preferably 40 or less,more preferably 30 or less, and further preferably 25 or less. Byadjusting the content of water in the mixture within the above range,crystallization may be promoted. In addition, the productivity perreactor may be increased. Further it is advantageous becausedeterioration of the mixing property by stirring due to increase inviscosity during the reaction may be suppressed, and the waste liquidtreatment cost may be curtailed.

Although there is no particular restriction on the amount of a seedcrystal added to the mixture, its content with respect to SiO₂, whereinsilicon (Si) included in the mixture other than the seed crystal isassumed to be totally SiO₂, is usually 0.1 mass % or more, preferably 1mass % or more, more preferably 2 mass % or more, and further preferably4 mass % or more; and the upper limit is usually 20 mass % or less,preferably 15 mass % or less, more preferably 10 mass % or less, andfurther preferably 8 mass % or less, provided that there is noparticular restriction thereon. By adjusting the amount of a seedcrystal within the above range, the amount of the precursor directed tothe CON framework becomes sufficient and crystallization may bepromoted. Further, since the amount of components derived from the seedcrystal to be contained in the product is suppressed, and theproductivity may be enhanced, the production cost may be reduced.

(Preparation of Reactant Mixture)

In the production method according to the present embodiment, a reactantmixture prepared by mixing the aforedescribed silicon source, aluminumsource, alkali metal source, and/or alkaline earth metal source, organicstructure-directing agent, and water is subjected to hydrothermalsynthesis. Although there is no particular restriction on the mixingorder of these raw materials, it is preferable that firstly water, analkali metal element source and/or an alkaline earth metal elementsource, and an organic structure-directing agent are mixed to prepare analkaline solution, and then an aluminum source, a silicon source, and,if necessary, a seed crystals are mixed in this order, because the rawmaterials may be dissolved more uniformly if a silicon source, and analuminum source are added after the alkaline solution is prepared.

(Maturing)

The reactant mixture prepared as described above may be subjected tohydrothermal synthesis immediately after its preparation, but the samemay be matured for a certain period of time under a predeterminedtemperature condition in order to obtain a zeolite having highcrystallinity. Especially in scaling-up, the stirring property is likelyto deteriorate and the mixed state of raw materials tends to beinsufficient. Therefore, it is preferable to improve the reactionmixture into a more uniform state by means of maturing with stirring fora certain period of time. The maturing temperature is usually 100° C. orless, preferably 95° C. or less, and more preferably 90° C. or less; andis usually 0° C. or more, and preferably 10° C. or more, although thelower limit thereof is not particularly provided. The maturingtemperature may be constant throughout the maturing, or it may bechanged stepwise or continuously. Although there is no particularrestriction on the maturing time, it is usually 2 hours or more,preferably 3 hours or more, and more preferably 5 hours or more; and isusually 14 days or less, preferably 7 days or less, and more preferably3 days or less.

(Hydrothermal Synthesis Step)

A CON zeolite may be produced by heating the mixture in a reactor(hydrothermal synthesis).

There is no particular restriction on the heating temperature (reactiontemperature), and it is usually 120° C. or more, preferably 140° C. ormore, more preferably 160° C. or more, and further preferably 170° C. ormore; and is usually 220° C. or less, preferably 200° C. or less, morepreferably 190° C. or less, and further preferably 185° C. or less. Byadjusting the reaction temperature within the above range, thecrystallization time of a CON zeolite may be shortened, and the yield ofzeolite is improved. In addition, it is preferable because by-productionof a zeolite having a different structure may be suppressed. Thereaction temperature may be constant throughout the reaction, or it maybe changed stepwise or continuously.

There is no particular restriction on the time required for raising thetemperature to the heating temperature (reaction temperature), and it isusually 0.1 hour or more, preferably 0.5 hours or more, and morepreferably 1 hour or more, and there is no particular upper limit of thetime required for raising the temperature.

The heating time (reaction time) is usually 1 hour or more, preferably 5hours or more, and more preferably 10 hours or more; and the upper limitis usually 30 days or less, preferably 10 days or less, more preferably7 days or less, and further preferably 5 days or less. By adjusting thereaction time within the above range, the yield of a CON zeolite may beimproved, and by-production of a zeolite having a different structuremay be suppressed, which is preferable.

There is no particular restriction on the pressure at the time of thereaction, and an autogenous pressure generated when a hermeticallyclosed container filled with the mixture is heated to the abovetemperature range suffices. If necessary, an inert gas such as nitrogenmay be added.

(Collection of CON Zeolite)

After the hydrothermal synthesis, the product CON zeolite is separatedfrom the hydrothermal synthesis reaction solution.

The obtained zeolite (hereinafter referred to as “zeolite containingSDA, etc.”) contains either or both of an organic structure-directingagent and an alkali metal in the pores. There is no particularrestriction on a method for separating a zeolite containing SDA, etc.from the hydrothermal synthesis reaction solution, and examples thereofusually include a method, such as filtration, decantation, and directdrying.

A zeolite containing SDA, etc. separated and collected from thehydrothermal synthesis reaction solution is, for removing an organicstructure-directing agent, etc. used during production, washed withwater and dried according to need and thereafter subjected tocalcination, etc. to yield a zeolite not containing an organicstructure-directing agent. From the viewpoint of production efficiency,removal by calcination is desirable.

When a CON zeolite of the present embodiment is used for an applicationof a catalyst (including a catalyst carrier), an adsorbent, and thelike, it is used, if necessary, after removing them,

The calcination temperature is usually 350° C. or higher, preferably400° C. or higher, and more preferably 450° C. or higher; and the upperlimit is usually 900° C. or lower, preferably 850° C. or lower, and morepreferably 800° C. or lower. By adjusting the calcination temperaturewithin the above range, a structure-directing agent may be efficientlyremoved, and the pore volume of the zeolite becomes sufficiently large.Further, collapse of zeolite framework and decrease in crystallinity maybe suppressed.

There is no particular restriction on the calcination time, insofar as astructure-directing agent is sufficiently removed. It is preferably 1hour or more, and more preferably 3 hours or more; and the upper limitis usually 24 hours or less.

The calcination is preferably carried out in an atmosphere containingoxygen, and is usually carried out in an air atmosphere.

Although there is no particular restriction on the application of a CONzeolite of the present embodiment, it is favorably used as a catalyst,an adsorbent, a separation material, or the like. In particular, it isfavorably used as a hydrocarbon adsorbent, a catalyst for purifying anexhaust gas of an automobile, etc. In particular, a CON zeolite havingan Al/Si ratio of 0.04 or more may obtain high adsorption performanceand catalytic activity.

3. Method of Producing Lower Olefin and Aromatic Hydrocarbon

The present embodiment has also an aspect as a method of producing alower olefin and an aromatic hydrocarbon from an organic compound rawmaterial. That is, it may be favorably used for producing lower olefinsby interconversion of lower olefins such as ethylene and propylene, andfor producing an aromatic hydrocarbon by a dehydrocyclization reaction.It may also be favorably used for producing a lower olefin (MTO:methanol to olefin) and for producing an aromatic hydrocarbon (methanolto aromatics) by conversion of a raw material containing an oxygenate,such as methanol and dimethyl ether.

(Ethylene)

There is no particular restriction on ethylene, which is a raw materialaccording to the present embodiment. For example, ethylene produced bycatalytic cracking or steam cracking from a petroleum source, ethyleneobtained by performing Fischer-Tropsch synthesis using as a raw materiala hydrogen/CO mixed gas obtained by gasification of coal, ethyleneobtained by dehydrogenation or hydrogenation of ethane, ethyleneobtained by a metathesis reaction and a homologation reaction, ethyleneobtained by a MTO (methanol to olefin) reaction, ethylene obtained by adehydration reaction of ethanol, ethylene obtained by oxidative couplingof methane, or ethylene obtained by any of various known methods may beused optionally. In this case, a mixture containing optionally anothercompound derived from various production methods in addition to ethylenemay be used as it is, however purified ethylene is preferable. Inaddition, since ethanol is immediately converted to ethylene bydehydration, ethanol may be used as it is as a raw material.

(Methanol, and Dimethyl Ether)

There is no particular restriction on the production origin of methanoland dimethyl ether, which are raw materials according to the presentembodiment. Examples of thereof include a product obtained by ahydrogenation reaction of a mixed gas of CO/hydrogen derived from aby-product in steel industry, coal, and natural gas; a product obtainedby a reforming reaction of alcohols of vegetable-origin; a productobtained by a fermentation method; and a product obtained from organicmaterials, such as recycled plastics and municipal waste. In this case,a mixture containing another compound derived from each productionmethods in addition to methanol and dimethyl ether may be used as it is,however purified mixture may be also used.

As a reaction raw material, only methanol may be used, only dimethylether may be used, or a mixture thereof may be used. When methanol anddimethyl ether are used as a mixture, there is no particular restrictionon the mixing ratio.

As a reaction raw material, at least one selected from methanol anddimethyl ether may be mixed with ethylene. When these are mixed andused, there is no particular restriction on the mixing ratio.

(Reactor)

There is no particular restriction on the reaction mode in the presentembodiment, insofar as an organic compound raw material is in a gasphase in the reaction zone, and a fixed bed reactor, a moving bedreactor, and a fluidized bed reactor may be selected. In thisconnection, although any form out of a batch, a semi-continuous, or acontinuous type may be carried out, a continuous type is preferable, andin such a case, either of a method using a single reactor, or a methodusing a plurality of reactors arranged in series or in parallel may beconducted.

When a fluidized bed reactor is filled with the catalyst, a granularmaterial inert to the reaction, such as quartz sand, alumina, silica,and silica-alumina may be mixed with the catalyst for filling in orderto control the temperature distribution of the catalyst layer to benarrow. In this case, there is no particular restriction on the usageamount of the granular material inert to the reaction, such as quartzsand. In this regard, it is preferable that the granular material has aparticle diameter similar to the catalyst from the viewpoint of uniformmixing with the catalyst.

A reaction substrate (reaction raw material) may be fed to the reactordivisionally for the sake of dispersing heat to be generated by thereaction.

(Substrate Concentration)

Although there is no particular restriction on the total concentrationof organic compound raw materials (substrate concentration) in all thesupply components to be supplied to the reactor, it is usually 5 mol %or more of the total supply, preferably 10 mol % or more, morepreferably 20 mol % or more, further preferably 30 mol % or more, andespecially preferably 50 mol or more; and is usually 95 mol % or less,preferably 90 mol % or less, and more preferably 70 mol % or less. Byadjusting the substrate concentration within the above range, formationof a heavy hydrocarbon component and a paraffin may be suppressed, andthe yield of a lower olefin and an aromatic hydrocarbon may be improved.Further, since the reaction rate may be maintained, the amount ofcatalyst may be suppressed and the size of the reactor may besuppressed.

Therefore, it is preferable to dilute the reaction substrate with adiluent described below according to need so as to realize such apreferable substrate concentration.

(Diluent)

In the reactor, in addition to the organic compound raw materials, a gasinert to the reaction including helium, argon, nitrogen, carbonmonoxide, carbon dioxide, hydrogen, water, paraffins, hydrocarbons suchas methane, aromatic compounds, and mixtures thereof may be present; andcoexistence of helium, nitrogen, and water (steam) is favorable, becauseseparation is easy.

As such a diluent, impurities contained in the reaction raw materialsmay be used as they are, or a diluent prepared separately may be mixedwith the reaction raw materials and used.

Further, the diluent may be mixed with the reaction raw material beforeentering the reactor, or may be supplied to the reactor separately fromthe reaction raw material.

(Weight Space Velocity)

The weight space velocity referred to herein is the flow rate of anorganic compound as the reaction raw material per weight of the catalyst(catalytically active component), wherein the weight of the catalystmeans the weight of a catalytically active component excluding aninactive component and a binder to be used for granulation or forming ofthe catalyst.

Further, the flow rate means the total flow rate (weight/hour) of theorganic compound raw materials (ethylene, and/or methanol, and/ordimethyl ether, etc.).

Although there is no particular restriction on the weight spacevelocity, it is usually 0.01 Hr⁻¹ or more, preferably 0.1 Hr⁻¹ or more,more preferably 0.3 Hr⁻¹ or more, and further preferably 0.5 Hr⁻¹; andis usually 50 Hr⁻¹ or less, preferably 20 Hr⁻¹ or less, more preferably10 Hr⁻¹ or less, and further preferably 5.0 Hr⁻¹ or less. By adjustingthe weight space velocity within the above range, the proportion of anunreacted organic compound raw material in the reactor outlet gas may bereduced, and the amount of by-products such as heavy hydrocarboncomponents and paraffins may be reduced, so that the yield of a lowerolefin and an aromatic hydrocarbon may be improved. In addition, bydoing so, the amount of catalyst necessary for obtaining a certainproduction amount may be reduced, which is preferable for suppressingthe size of the reactor.

(Reaction Temperature)

There is no particular restriction on the reaction temperature, insofaras it is a temperature at which a lower olefin and an aromatichydrocarbon is formed when an organic compound raw material gets incontact with a catalyst. It is usually 250° C. or higher, preferably300° C. or higher, more preferably 350° C. or higher, and furtherpreferably 400° C. or higher; and is usually 650° C. or lower,preferably 600° C. or lower, more preferably 550° C. or lower, andfurther preferably 500° C. or lower. By adjusting the reactiontemperature within the above range, the productivity may be increasedwhile suppressing coking. Further, since aluminum elimination from thezeolite framework is suppressed, the catalyst life may be maintained,which is preferable. In this regard, the reaction temperature meansherein the temperature at the outlet of the catalyst layer.

(Reaction Pressure)

Although there is no particular restriction on the reaction pressure, itis usually 0.01 MPa or more (absolute pressure, the same applieshereinbelow), preferably 0.05 MPa or more, more preferably 0.1 MPa ormore, and further preferably 0.2 MPa or more; and is usually 5 MPa orless, preferably 1 MPa or less, more preferably 0.7 MPa or less, andfurther preferably 0.5 MPa or less. When the reaction pressure is withinthe above range, the yield of a lower olefin and an aromatic hydrocarbonmay be improved.

(Raw Material Partial Pressure)

Although there is no particular restriction on the total partialpressure of organic compound raw materials, it is usually 0.005 MPa ormore (absolute pressure, the same applies hereinbelow), preferably 0.01MPa or more, more preferably 0.03 MPa or more, further preferably 0.05MPa or more, and especially preferably 0.07 MPa or more; and is usually3 MPa or less, preferably 1 MPa or less, more preferably 0.5 MPa orless, further preferably 0.3 MPa or less, and especially preferably 0.1MPa or less. By adjusting the partial pressures of a raw materialswithin the above range, coking may be suppressed and the yield of alower olefin and an aromatic hydrocarbon may be improved. The reactionrate may also be maintained.

(Conversion)

Although there is no particular restriction on the conversion ofmethanol and/or dimethyl ether in the present embodiment, the conversionis usually 90% or more, preferably 95% or more, more preferably 99% ormore, and further preferably 99.5% or more; and is usually 100% or less.Meanwhile, although the conversion of ethylene is not particularlylimited, the conversion is usually 50% or more, preferably 60% or more,and more preferably 70% or more; and is usually less than 100%,preferably 95% or less, and more preferably 90% or less.

Usually with the reaction time, accumulation of coke proceeds, and theconversion of an organic compound raw material tends to decrease.Therefore, the catalyst used for the reaction for a certain period oftime needs to be subjected to a regeneration treatment. There is noparticular limitation on a method of operation in the above conversionrange.

For example, when a reaction is carried out in a fixed bed reactor, aplurality of reactors are provided in parallel, and when the conversionfalls below the above preferable range, the contact between the catalystand the reaction raw material is stopped and the catalyst is subjectedto a regeneration step. In a fixed bed reactor, the reaction time andthe regeneration time are adjusted appropriately, in other words, theswitching timing from a reaction step to a regeneration step duringoperation is regulated appropriately so that the operation may becarried out continuously at a conversion in the above preferred range.

In a case in which the reaction is conducted in a fluidized bed reactor,it is preferable to attach a catalyst regenerator to the reactor and toperform the reaction while transferring continuously the catalystdischarged from the reactor to the regenerator, and returningcontinuously the catalyst regenerated in the regenerator to the reactor.By adjusting appropriately the residence time of the catalyst in thereactor and the residence time in the regenerator, it is possible toperform the operation continuously at a conversion in the abovepreferred range.

A catalyst which conversion of an organic compound raw material has beendeclined may be regenerated utilizing various known catalystregenerating methods.

Although there is no particular restriction on the regeneration method,specifically it may be regenerated using, for example, air, nitrogen,steam, or hydrogen, and regeneration using air or hydrogen ispreferable.

(Reaction Product)

As the reactor outlet gas (reactor effluent), a mixed gas containing alower olefin, such as ethylene, propylene, and butene, an aromatichydrocarbon, such as benzene, toluene, and xylene, as reaction products,as well as a by-product and a diluent is obtained. Although there is noparticular restriction on the concentration of the target components inthe mixed gas, it is usually 5 mass % or more, and preferably 10 mass %or more; and is usually 95 mass % or less, and preferably 90 mass % orless.

Depending on the reaction conditions, an unreacted raw material may beincluded in the reaction product, it is preferable to carry out thereaction under such reaction conditions that the amount of the unreactedraw material becomes minimal. By doing so, separation of the reactionproduct from the unreacted raw material becomes easy, and preferablyunnecessary.

(Separation of Product)

The mixed gas as the reactor outlet gas containing a lower olefin and anaromatic hydrocarbon as the reaction products, an unreacted rawmaterial, a by-product and a diluent, may be introduced into a knownseparation and purification facility, and subjected to treatments forcollection, purification, recycling, and discharging corresponding toeach component.

4. Adsorbent

Another aspect of the present invention also has an aspect as anadsorbent for an inorganic gas or a hydrocarbon component. Specifically,it relates to a use as an adsorbent for a hydrocarbon gas, especiallyfor an exhaust gas as formed during combustion of a hydrocarbon, andmore specifically it relates to adsorption of a hydrocarbon gas formedin a cold start operation of an internal combustion engine.

Prospective low emission standards for vehicles force automobilemanufacturers and catalyst manufacturers to focus on reduction ofhydrocarbon emissions during a cold start. This is because a largeportion of the hydrocarbon emissions occur during the cold start period.Therefore, it is essential to control the emissions during a cold startoperation of a vehicle equipped with an internal combustion engine. Afresh catalyst begins to function at a relatively low temperature around170° C., but in the case of a catalysts used for many years the minimumfunctioning temperature rises and the catalyst begins to function atabout 200° C. to 220° C. Such a catalyst usually requires at least 1 to2 min to reach such temperatures, and approximately 70% of thehydrocarbon emission occurs in the low temperature range. In otherwords, at lower temperatures, where the catalyst in the catalyticconverter is not able to convert effectively an incompletely combustedhydrocarbon to the final combustion products, it is desired that ahydrocarbon adsorbent adsorbs to trap the hydrocarbons discharged froman engine (hydrocarbon trap, HC trap) before they reach the catalyticconverter. The desorption temperature is preferably equal to or higherthan the activation temperature of the catalyst.

An important requirement for a hydrocarbon trapping material is theadsorption ability of the adsorbent, that is, the desorption temperatureat which an adsorbed hydrocarbon is desorbed and sent to a catalyticconverter, and the hydrothermal stability of the adsorbent.

Various zeolites having a BEA framework have been heretoforeinvestigated as a hydrocarbon trapping material. However, it has beenfound that a BEA zeolite has insufficient hydrothermal stability, andthe decline of the adsorption ability advances over a prolonged use.Therefore, there is a demand for a hydrocarbon trapping material capableof adsorbing and trapping a hydrocarbon component discharged during acold start of an internal combustion engine (period until the catalystis activated).

A CON zeolite of the present embodiment has a high adsorption abilityand a high hydrothermal stability that can withstand a limited space dueto an automobile on-board use, and a wide range of exhaust gasenvironment associated with engine operating conditions. Therefore, itmay be favorably used as a hydrocarbon trapping material.

For an application as a hydrocarbon trapping material, a CON zeolite ofthe present embodiment may be used singly, or in a mixture with otherzeolites.

Further, an adsorbent containing a CON zeolite of the present embodimentmay be mixed and formed with a binder, such as silica, alumina, and aclay mineral. Examples of the clay mineral include kaolin, sepiolite,montmorillonite, bentonite, attapulgite, and talc. It may be applied toa substrate such as a honeycomb and used. Specifically, for example, aslurry is prepared by mixing a catalyst containing a CON zeolite of thepresent embodiment, and an inorganic binder, such as silica, alumina,and a clay mineral, and may be applied to the surface of a substratemade of an inorganic material such as cordierite, and used.

The target gas to be adsorbed is, for example, a gas contained in anexhaust gas of an internal combustion engine of a gasoline engine car, adiesel engine car, or the like. Specific examples thereof include aninorganic gas, such as carbon monoxide, carbon dioxide, nitrogen,oxygen, hydrogen, water, sulfur compounds, and nitrogen oxides, and ahydrocarbon gas. Regarding the hydrocarbon gas, a CON zeolite of thepresent embodiment is effective especially in adsorbing an alkane havinga carbon number of approx. 1 to 20, such as methane, ethane, propane,butane, pentane, hexane, n-heptane, and isooctane; an alkene having acarbon number of approx. 2 to 20, such as ethylene, propylene, butene,pentene, methylpentene, hexene, and methylhexene; and aromatics, such asbenzene, toluene, xylene, and trimethylbenzene. The zeolite may be usedfor a single kind of hydrocarbon of the above target gases, or used fora mixture of a plurality of hydrocarbons. When a CON zeolite of thepresent embodiment is used, the plural kinds of hydrocarbons may beadsorbed at the same time.

Although there is no particular restriction on the contact conditionbetween an adsorbent and an exhaust gas in using an adsorbent containinga CON zeolite of the present embodiment, it is usually 100 hr⁻¹ or more,preferably 1,000 hr⁻¹ or more, and further preferably 5,000 hr⁻¹ ormore; and is usually 500,000 hr⁻¹ or less, preferably 400,000 hr⁻¹ orless, and further preferably 200,000 hr⁻¹ or less.

Although there is no particular restriction on the temperature in usingan adsorbent containing a CON zeolite of the present embodiment, it isusually 50° C. or more, more preferably 100° C. or more, furtherpreferably 120° C. or more, and especially preferably 150° C. or more;and is usually 800° C. or less, preferably 600° C. or less, morepreferably 400° C. or less, and especially preferably 300° C. or less.

5. Exhaust Gas Treatment Catalyst

When a CON zeolite of the present embodiment is used as an exhaust gastreatment catalyst such as a catalyst for purifying an automobileexhaust gas, the CON zeolite of the present embodiment may be used as itis, or a CON zeolite to which a metal is added according to need may beused. Specific examples of a method of adding a metal include a methodof impregnation, and a method of ion exchange in a liquid phase or asolid phase. Alternatively, a metal-containing zeolite may besynthesized directly by adding a metal (which may be an elementarysubstance, or a compound) before the hydrothermal synthesis as describedabove. As for the presence state of the metal in a metal-containingzeolite, it may be included in the framework, or not included in theframework. Further, it may be used also after being mixed with a binder,such as silica, alumina, and a clay mineral, and granulated or formed.Further, it may be used after being formed into a predetermined shape bya coating method or a forming method, and it may preferably be usedafter being formed into a honeycomb shape.

When a formed body of a catalyst containing a CON zeolite of the presentembodiment is yielded by the coating method, the same may be yieldedusually by mixing a CON zeolite of the present embodiment with aninorganic binder, such as silica, and alumina, to prepare a slurry,applying the slurry to the surface of a formed body made of an inorganicmaterial such as cordierite, and performing calcination. By doing so,the slurry is preferably coated on a honeycomb-shaped formed body so asto yield a honeycomb catalyst. Since the above describes an example ofan exhaust gas treatment catalyst, an inorganic binder is used, howeveran organic binder may be also used depending on the application and useconditions.

When a formed body of a catalyst containing a CON zeolite of the presentembodiment is yielded by the forming method, the same may be yieldedusually by kneading a CON zeolite with an inorganic binder such assilica and alumina, and an inorganic fiber such as an alumina fiber anda glass fiber, forming them by an extrusion method or a compressionmethod, and performing calcination. Preferably, by doing so, a honeycombcatalyst may be yielded by forming into a honeycomb shape.

A catalyst of the present embodiment including a CON zeolite of thepresent embodiment is effective as a selective reduction catalyst forNOx such as an automobile exhaust gas purification catalyst for removingnitrogen oxides by bringing it into contact with a nitrogenoxide-containing exhaust gas.

An exhaust gas treatment catalyst, in which a metal other than Si and Alis added to a CON zeolite of the present embodiment, is especiallyeffective as a selective reduction catalyst for NOx. With respect to anexhaust gas treatment catalyst, the metal element to be added to thezeolite is preferably a transition metal, and among others the oneselected from the group including iron, cobalt, palladium, iridium,platinum, copper, silver, gold, cerium, lanthanum, praseodymium,titanium, and zirconium is preferable. More preferably, it is selectedfrom iron and copper. Two or more of these metals may be added incombination. Cu (copper) is the most preferable. The content of metalelements other than Si and Al with respect to the total amount of CONzeolite to which the metal elements other than Si and Al are added isusually 0.1 weight % or more, preferably 0.3 weight % or more, morepreferably 0.5 weight % or more, and especially preferably 1.0 weight %or more; and is usually 20 weight % or less, preferably 10 weight % orless, and more preferably 8 weight % or less.

Especially, when the metal element to be added into the zeolite iscopper (Cu), the content thereof in the catalyst is preferably 0.1weight % or more and 10 weight % or less, and a more preferable range isas described above.

Although there is no particular restriction on the method for adding themetal into a CON zeolite of the present embodiment, a method by whichthe metal is supported by a CON zeolite, such as an ion exchange method,an impregnation method, a precipitation method, a solid phase ionexchange method, a CVD method, and a spray-drying method, which arecommonly used, and more preferable are a solid phase ion exchangemethod, an impregnation method, and a spray-drying method.

There is no particular restriction on a metal raw material, and usuallyan inorganic acid salt, such as a sulfate, a nitrate, a phosphate, achloride, and a bromide; an organic acid salt, such as an acetate, anoxalate, and a citrate; and an organometallic compound, such as apentacarbonyl and a ferrocene, and the like of the above metals areused. Among the above, from the viewpoint of solubility in water, aninorganic acid salt and an organic acid salt are preferable, and morespecifically, for example, a nitrate, a sulfate, an acetate, ahydrochloride, etc. are preferable. In some cases, a colloidal oxide ora fine powder oxide may be used.

As metal raw materials, two or more different kinds of metal species orcompound species may be used in combination.

After the metal has been supported on a CON zeolite, it is calcinedpreferably at 300° C. to 900° C., more preferably at 350° C. to 850° C.,and further preferably at 400° C. to 800° C., and for 1 sec to 24 hours,preferably 10 sec to 8 hours, more preferably about 30 min to 4 hours.Although this calcination is not necessarily required, it is effectiveto conduct calcination for improving the dispersibility of the metalsupported in the framework of the zeolite so as to enhance the catalyticactivity.

Although there is no particular restriction on the specific surface areaof a catalyst yielded in the present embodiment, it is preferably from300 to 1000 m²/g, more preferably from 350 to 800 m²/g, and furtherpreferably from 450 to 750 m²/g because the number of active sitespresent on the inner surface of the pores increases. In this regard, thespecific surface area of a catalyst is measured by the BET method.

The exhaust gas may include components other than nitrogen oxides andmay include, for example, a hydrocarbon, carbon monoxide, carbondioxide, hydrogen, nitrogen, oxygen, sulfur oxides, and water. When thecatalyst is used, a known reducing agent, such as a hydrocarbon, and anitrogen-containing compound including ammonia, urea, or the like, maybe used. Specifically, nitrogen oxides contained in various exhaustgases discharged from various types of diesel engines, boilers, gasturbines, etc. of a diesel engine automobile, a gasoline engineautomobile, a stationary power generator, a ship, an agriculturalmachine, a construction machine, a motorcycle, and an aircraft, may beremoved by an exhaust gas treatment catalyst of the present embodiment.

A CON zeolite of the present embodiment may be used in addition to theuse as catalysts for removing nitrogen oxides, for example, in a stepsubsequent to the step where nitrogen oxides are removed using acatalyst for removing nitrogen oxides of the present embodiment, as anoxidation catalyst, which oxidizes an excessive reducing agent (forexample, ammonia) not having been consumed in removing nitrogen oxides.In this way a catalyst containing a CON zeolite of the presentembodiment is capable of oxidizing an excessive reducing agent as anoxidation catalyst to decrease the reducing agent in an exhaust gas. Inthat case, a catalyst, in which a metal such as the platinum group issupported on a carrier such as zeolite for adsorbing the reducing agent,may be used as an oxidation catalyst, and a CON zeolite of the presentembodiment may be used as the carrier, or as a selective reductioncatalyst for nitrogen oxides. For example, a CON zeolite of the presentembodiment supporting, for example, iron and/or copper may be used aftersupporting additionally a metal such as the platinum group.

Although there is no particular restriction on the contact condition ofa catalyst with an exhaust gas when a catalyst of the present embodimentis used, the space velocity of the exhaust gas is usually 100 hr⁻¹ ormore, preferably 1,000 hr⁻¹ or more, and more preferably 5,000 hr⁻¹ ormore; and is usually 500,000 hr⁻¹ or less, preferably 400,000 hr⁻¹ orless, and more preferably 200,000 hr⁻¹ or less. Further, the temperatureis usually 100° C. or higher, preferably 125° C. or higher, and morepreferably 150° C. or higher; and is usually 1000° C. or lower,preferably 800° C. or lower, more preferably 600° C. or lower, andespecially preferably 500° C. or lower.

Another aspect of the present invention will be described in more detailwith reference to Example A, but it is not limited to the followingExamples unless it departs from the scope and spirit of the presentinvention.

An X-ray diffraction (XRD) pattern of a crystal of a zeolite obtained bythe synthesis in the following Preparation Example A was obtained usingan X′ Pert PRO MPD produced by Malvern Panalytical B.V. The X-ray sourceis CuKα (X-ray output: 40 kV, 30 mA), the reading width is 0.016° andthe scanning speed is 4.0°/min. In addition, the shape of the particlewas observed on a sample having undergone a conductive treatment using ascanning electron microscope (ULTRA 55) produced by Carl Zeiss at anacceleration voltage of 3 kV. The composition of the synthesized zeolitewas determined by an ICP elemental analysis based on inductively-coupledplasma atomic emission spectrometry (ICP-AES). For a fluorescent X-rayanalysis (XRF), a Rayny EDX-700 produced by Shimadzu Corporation wasused.

Preparation Example A

Firstly, 2.57 g of sodium hydroxide (97 mass % or more, produced byKishida Chemical Co., Ltd.), 288 g of an aqueous solution ofN,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (hereinafterabbreviated as “TMMAOH”) (14.8 mass %, produced by Wako Pure ChemicalIndustries, Ltd.), 2.47 g of boric acid (produced by Kishida ChemicalCo., Ltd.), and 0.407 g of aluminum sulfate (51.0 to 57.5 mass %,produced by Kishida Chemical Co., Ltd.) were mixed, to which 197 g ofsilica sol SI-30 (SiO₂: 30.6 mass %, and Na₂O: 0.37 mass %, produced byJGC Catalysts and Chemicals Ltd.) was added as a silica source, and themixture was stirred sufficiently. Further, 1.20 g of a BEA zeolite(SiO₂/Al₂O₃ ratio: 30, HSZ-931 HOA produced by Tosoh Corporation)equivalent to 2 mass % with respect to the added SiO₂ was added as aseed crystal and stirring was continued further to obtain a mixture. Themixture was charged in a 1000 mL autoclave, and subjected to ahydrothermal synthesis reaction at 170° C. for 4 days with stirring at250 rpm under an autogenous pressure. The obtained product wasfiltrated, washed with water, and dried at 100° C. to obtain 58.9 g of awhite powder. From the XRD pattern of the product, it was confirmed thatthe obtained product was a CON zeolite. From an ICP elemental analysis,the SiO₂/Al₂O₃ ratio was 595 and the SiO₂/B₂O₃ ratio was 50.

Example A1

Firstly, 0.155 g of sodium hydroxide, 4.16 g of an aqueous solution ofN,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8 mass %), and3.65 g of water were mixed, to which 0.960 g of zeolite Y CBV 720(SiO₂/Al₂O₃ ratio: 30, produced by Zeolyst International), and 0.990 gof colloidal silica SI-30 (SiO₂: 30 mass %, Na₂O: 0.4 mass %, producedby JGC Catalysts and Chemicals Ltd.) were added, and the mixture wasstirred for 2 hours. Further, 0.240 g of zeolite CIT-1 (SiO₂/Al₂O₃ratio: 595, SiO₂/B₂O₃ ratio: 50) equivalent to 20 mass % with respect tothe added SiO₂ was added as a seed crystal and stirring was continuedfurther to obtain a mixture. The mixture was charged in a 100 mLautoclave, and subjected to a hydrothermal synthesis reaction at 160° C.for 4 days with stirring at 15 rpm under an autogenous pressure. Theobtained product was filtrated, washed with water, and dried at 100° C.to obtain 0.98 g of a white powder. From the XRD pattern of the product(Table 4), it was confirmed that the obtained product was a CON zeolite.From the SEM image, the average primary particle diameter was 0.20 μm.

After removal of the organic structure-directing agent by calcination at600° C. for 6 hours in an air stream, the S±O₂/Al₂O₃ ratio determined by²⁹Si-NMR was 32.

TABLE 4 Relative Intensity 2θ (°) d (Å) [I/Io × 100] 7.74 11.41 100 8.3510.58 15 8.96 9.86 27 13.14 6.73 16 14.14 6.26 10 15.17 5.84 16 15.635.67 13 16.67 5.31 7 18.04 4.91 8 19.56 4.54 21 20.20 4.39 53 21.27 4.1725 21.90 4.06 46 22.86 3.89 59 23.83 3.73 11 24.20 3.68 11 25.07 3.55 1326.46 3.37 30 27.66 3.22 8 27.96 3.19 9 28.59 3.12 12 28.90 3.09 1129.59 3.02 8 30.25 2.95 9 30.78 2.90 7 31.43 2.84 8 31.84 2.81 8 33.132.70 8 35.25 2.54 8 35.65 2.52 7 36.82 2.44 7 37.17 2.42 7

Example A2

Firstly, 0.160 g of sodium hydroxide, 4.16 g of an aqueous solution ofN,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8 mass %), and4.33 g of water were mixed, to which 1.24 g of zeolite Y CBV 760(SiO₂/Al₂O₃ ratio: 60, produced by Zeolyst International) was added, andthe mixture was stirred for 2 hours. Further, 0.240 g of zeolite CIT-1(SiO₂/Al₂O₃ ratio: 595, SiO₂/B₂O₃ ratio: 50) equivalent to 20 mass %with respect to the added SiO₂ was added as a seed crystal and stirringwas continued further to obtain a mixture. The mixture was charged in a100 mL autoclave, and subjected to a hydrothermal synthesis reaction at160° C. for 4 days with stirring at 15 rpm under an autogenous pressure.The obtained product was filtrated, washed with water, and dried at 100°C. to obtain 0.86 g of a white powder. From the XRD pattern of theproduct, it was confirmed that the obtained product was a CON zeolite.

Example A3

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA2 except that 1.23 g of CBV 780 (SiO₂/Al₂O₂ ratio: 80, produced byZeolyst International) was used as the zeolite Y. The post-treatment(filtration, washing with water, and drying) was carried out in the samemanner as in Example A2 to obtain 0.71 g of a white powder. From the XRDpattern of the product, it was confirmed that the obtained product was aCON zeolite.

Example A4

Firstly, 0.198 g of potassium hydroxide, 1.39 g of an aqueous solutionof N,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8 mass %), and2.23 g of water were mixed, to which 0.510 of zeolite Y HSZ-360 HUA(SiO₂/Al₂O₂ ratio: 15, produced by Tosoh Corporation), and 0.492 g ofcolloidal silica SI-30 were added, and the mixture was stirred for 2hours. Further, 0.120 g of zeolite CIT-1 (SiO₂/Al₂O₃ ratio: 595,SiO₂/B₂O₃ ratio: 50) equivalent to 20 mass % with respect to the addedSiO₂ was added as a seed crystal and stirring was continued further toobtain a mixture. The mixture was charged in a 100 mL autoclave, andsubjected to a hydrothermal synthesis reaction at 180° C. for 2 dayswith stirring at 15 rpm under an autogenous pressure. The obtainedproduct was filtrated, washed with water, and dried at 100° C. to obtain0.64 g of a white powder. From the XRD pattern of the product, it wasconfirmed that the obtained product was a CON zeolite.

Example A5

Firstly, 0.231 g of potassium hydroxide, 0.693 g of an aqueous solutionof N, N, N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8 mass %),and 1.69 g of water were mixed, to which 0.095 g of aluminum hydroxide(53.5 mass % in terms of aluminum oxide, produced by Sigma-Aldrich), and1.97 g of colloidal silica SI-30 were added, and the mixture was stirredfor 2 hours. Further, 0.120 g of zeolite CIT-1 (SiO₂/Al₂O₃ ratio: 595,SiO₂/B₂O₃ ratio: 50) equivalent to 20 mass % with respect to the addedSiO₂ was added as a seed crystal, and stirring was continued further toobtain a mixture. The mixture was charged in a 100 mL autoclave, andsubjected to a hydrothermal synthesis reaction at 180° C. for 4 dayswith stirring at 15 rpm under an autogenous pressure. The obtainedproduct was filtrated, washed with water, and dried at 100° C. to obtain0.72 g of a white powder. From the XRD pattern of the product, it wasconfirmed that the obtained product was a CON zeolite.

Example A6

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA5 except that 0.076 g of aluminum hydroxide was added. Thepost-treatment (filtration, washing with water, and drying) was carriedout in the same manner as in Example A5 to obtain 0.66 g of a whitepowder. From the XRD pattern of the product, it was confirmed that theobtained product was a CON zeolite. From the SEM image, the averageprimary particle diameter was 0.10 μm.

Example A7

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.060 g of zeolite CIT-1 (SiO₂/Al₂O₃ ratio: 595,SiO₂/B₂O₃ ratio: 50) equivalent to 10 mass c, with respect to the addedSiO₂ was added as a seed crystal. The post-treatment (filtration,washing with water, and drying) was carried out in the same manner as inExample A6 to obtain 0.61 g of a white powder. From the XRD pattern ofthe product, it was confirmed that the obtained product was a CONzeolite.

Example A8

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.165 g of potassium hydroxide, 1.73 g of an aqueoussolution of N,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8mass %), and 0.985 g of water were added. The post-treatment(filtration, washing with water, and drying) was carried out in the samemanner as in Example A6 to obtain 0.65 g of a white powder. From the XRDpattern of the product, it was confirmed that the obtained product was aCON zeolite.

Example A9

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.198 g of potassium hydroxide, 1.39 g of an aqueoussolution of N,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8mass %), and 1.22 g g of water were added. The post-treatment(filtration, washing with water, and drying) was carried out in the samemanner as in Example A6 to obtain 0.66 g of a white powder. From the XRDpattern of the product, it was confirmed that the obtained product was aCON zeolite.

Example A10

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA9 except that 0.060 g of zeolite CIT-1 (SiO₂/Al₂O₃ ratio: 595,SiO₂/B₂O₃ ratio: 50) equivalent to 10 mass % with respect to the addedSiO₂ was added as a seed crystal. The post-treatment (filtration,washing with water, and drying) was carried out in the same manner as inExample A9 to obtain 0.56 g of a white powder. From the XRD pattern ofthe product, it was confirmed that the obtained product was a CONzeolite.

Example A11

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.030 g of sodium hydroxide, 0.198 g of potassiumhydroxide, 0.693 g of an aqueous solution ofN,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8 mass %), and1.70 g of water were added. The post-treatment (filtration, washing withwater, and drying) was carried out in the same manner as in Example A6to obtain 0.60 g of a white powder. From the XRD pattern of the product,it was confirmed that the obtained product was a CON zeolite.

Example A12

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.165 g of potassium hydroxide, 0.088 g of cesiumhydroxide (produced by Mitsuwa Chemicals Co., Ltd.), 1.39 g of anaqueous solution of N,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide(30.8 mass %, and 1.22 g of water were added. The post-treatment(filtration, washing with water, and drying) was carried out in the samemanner as in Example A6 to obtain 0.67 g of a white powder. From the XRDpattern of the product, it was confirmed that the obtained product was aCON zeolite.

Example A13

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA5 except that 0.132 g of potassium hydroxide, 2.08 g of an aqueoussolution of N,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8mass %), 0.757 g of water, and 0.064 g of aluminum hydroxide were added.The post-treatment (filtration, washing with water, and drying) wascarried out in the same manner as in Example A5 to obtain 0.62 g of awhite powder. From the XRD pattern of the product, it was confirmed thatthe obtained product was a CON zeolite. From the SEM image (FIG. 7), theaverage primary particle diameter was 0.20 μm.

After removal of the organic structure-directing agent by calcination at600° C. for 6 hours in an air stream, the SiO₂/Al₂O₃ ratio determined by²⁹Si-NMR was 29.

Example A14

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA5 except that 0.198 g of potassium hydroxide, 1.39 g of an aqueoussolution of N,N,N-trimethyl-(−)-cis-myrtanylammonium hydroxide (30.8mass %), 1.22 g of water, and 0.048 g of aluminum hydroxide were added.The post-treatment (filtration, washing with water, and drying) wascarried out in the same manner as in Example A5 to obtain 0.51 g of awhite powder. From the XRD pattern of the product, it was confirmed thatthe obtained product was a CON zeolite.

Example A15

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA14 except that 0.032 g of aluminum hydroxide was added. Thepost-treatment (filtration, washing with water, and drying) was carriedout in the same manner as in Example A14 to obtain 0.47 g of a whitepowder. From the XRD pattern of the product, it was confirmed that theobtained product was a CON zeolite.

Example A16

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.120 g of the zeolite Al-CIT-1 obtained in Example A8was added. The post-treatment (filtration, washing with water, anddrying) was carried out in the same manner as in Example A6 to obtain0.65 g of a white powder. From the XRD pattern of the product, it wasconfirmed that the obtained product was a CON zeolite.

Example A17

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA6 except that 0.601 g of fumed silica AEROSIL 200 instead of thecolloidal silica SI-30, and 3.03 g of water were added. Thepost-treatment (filtration, washing with water, and drying) was carriedout in the same manner as in Example A6 to obtain 0.60 g of a whitepowder. From the XRD pattern of the product, it was confirmed that theobtained product was a CON zeolite.

Comparative Example A1

A mixture was prepared and subjected to a hydrothermal synthesisreaction in the same manner and under the same conditions as in ExampleA14 except that 0.010 g of aluminum hydroxide was added. Thepost-treatment (filtration, washing with water, and drying) was carriedout in the same manner as in Example A14 to obtain 0.35 g of a whitepowder. From the XRD pattern of the product, it was confirmed that theobtained product was a mixed phase of a cristobalite phase and partly aCON phase.

The synthesis conditions and synthesis results of Examples A1 to A17 andComparative Example A1 are shown in Table 5-1 or 5-2.

TABLE 5 Example Example Example Example Example Example Example ExampleA1 A2 A3 Example A4 A5 A6 A7 A8 A9 Raw materials Silicon source FAUzeolite FAU FAU FAU zeolite Cataloid SI-30 for synthesis (SAR30) zeolitezeolite (SAR15) Cataloid (SAR60) (SAR80) Cataloid SI-30 SI-30 AluminumFAU zeolite FAU FAU FAU zeolite Al(OH)₃ source (SAR30) zeolite zeolite(SAR15) (SAR60) (SAR80) Feed Al/Si 0.05 0.033 0.025 0.1 0.1 0.08 0.080.08 0.08 molar ratio NaOH/Si 0.2 0.2 0.2 0.02 0.02 0.02 0.02 0.02 0.02KOH/Si 0 0 0 0.3 0.35 0.35 0.35 0.25 0.3 Cs/Si 0 0 0 0 0 0 0 0 0 SDA/Si0.3 0.3 0.3 0.2 0.1 0.1 0.1 0.25 0.2 H₂O/Si 20 20 20 20 20 20 20 20 20Seed (mass %) 20 20 20 20 20 20 10 20 20 Hydrothermal Temperature 160160 160 180 180 180 180 180 180 synthesis (° C.) conditions Time (day) 44 4 2 4 4 4 4 4 Synthesis Crystal phase CON CON CON CON CON CON CON CONCON results Yield (%) 66 58 48 83 93 87 87 86 87 Si/Al₂ ratio 31 37 5018 19 22 21 — — Si/B₂ ratio 324 168 142 601 702 1111 1575 — — Acidcontent 1.1 — — — 0.75 — — — — (mmol/g) Particle 0.2 — — — — 0.1 — — —diameter (μm) Example Example Example Example Example Example ExampleExample Comparative A10 A11 A12 A13 A14 A15 A16 A17 Example A1 Rawmaterials Silicon source Cataloid SI-30 Fumed Cataloid for synthesisSilica SI-30 Aluminum Al(OH)₃ Al(OH)₃ Al(OH)₃ source Feed Al/Si 80 800.08 0.067 0.05 0.033 0.08 0.08 0.01 molar ratio NaOH/Si 2 0.1 0.02 0.020.02 0.02 0.02 0.02 0.02 KOH/Si 0.3 0.3 0.25 0.2 0.3 0.3 0.35 0.35 0.3Cs/Si 0 0 0.05 0 0 0 0 0 0 SDA/Si 0.2 0.1 0.2 0.3 0.2 0.2 0.1 0.1 0.2H₂O/Si 20 20 20 20 20 20 20 20 20 Seed (mass %) 10 20 20 20 20 20 20 2020 Hydrothermal Temperature 180 180 180 180 180 180 180 180 180synthesis (° C.) conditions Time (day) 4 4 4 4 4 4 4 4 4 SynthesisCrystal phase CON CON CON CON CON CON CON CON Cristobalite + results CONYield (%) 80 79 88 82 68 64 85 79 48 Si/Al₂ ratio 21 22 23 26 31 — — 22— Si/B₂ ratio 1389 897 2861 781 442 — — 1626 — Acid content — — — — — —— — — (mmol/g) Particle — — — 0.16 — — — — — diameter (μm)

The details of the raw materials used for the syntheses in Examples A1to A17, and Comparative Example A1 are as follows. NaOH (produced byKishida Chemical Co., Ltd.), KOH (produced by Kishida Chemical Co.,Ltd.), CsOH (produced by Mitsuwa Chemicals Co., Ltd.), and CataloidSI-30 (silica concentration: 30.6 weight %, produced by JGC Catalystsand Chemicals Ltd.)

A yield (weight %) was calculated according to the following formula.

(Yield)(Weight of CON zeolite including SDA(g))/[(Weight(g) of siliconraw material and aluminum raw material added during production in termsof SiO₂and Al₂O₃ respectively)+(Weight(g) of seed crystal zeolite)]×100

(Evaluation of Performance of Hydrocarbon Trapping Material)

In order to examine the adsorption characteristics of a CON zeolite ofthe present embodiment, desorbed toluene was detected by a massspectrometer based on temperature-programmed desorption (TPD) oftoluene. Approximately 100 mg of a zeolite sample was weighed on to a Ptboat, which was placed in a quartz tube, heated to 300° C. at 20° C./minin a helium stream of 50 cc/min, and allowed to stand there for 2 hoursto remove adsorbed water from zeolite. After cooling down to 50° C. thesystem was evacuate with a rotary pump (RP) and a turbo molecular pump(TMP). Next, toluene was introduced into a quartz tube in a vacuum stateat 50° C. to be adsorbed for 15 min. Thereafter, as a pre-desorptiontreatment, the temperature was raised to 90° C. at 10° C./min in ahelium stream of 50 cc/min, and kept there for 10 min (pre-desorptiontreatment step). Toluene temperature-programmed desorption was measuredafter heating a sample from 90° C. up to 390° C. at 20° C./min in ahelium stream of 50 cc/min, and allowing it to stand there for 10 min,by detecting the toluene freed in the course of the program with a massspectrometer. The toluene adsorption amount was calculated as follows.Since a water component was also detected together with toluene inperforming temperature-programmed desorption, a conversion factor forcalculating a water desorption amount was determined from the area ofthe m/z=18 peak in a mass spectrometry of calcium oxalate (CaC₂O₄.H₂O)as a reference substance. Further, a reference sample, on which toluenewas adsorbed, was prepared, and the TG-DTA loss in the range of 90° C.to 390° C. was measured. Such portion of the loss as exceeds the waterdesorption amount determined from the area of the m/z=18 peak in thetemperature-programmed desorption is deemed as the toluene desorptionamount, and a conversion factor for obtaining a toluene desorptionamount was calculated from the area of peak of the m/z=91 peak. Usingsuch conversion factors, the desorbed amount of toluene at the time oftemperature rise of a CON zeolite was calculated.

Example A18

The CON zeolite (Si/Al₂=31) obtained in Example A1 was calcined at 600°C. for 6 hours in an air stream to obtain a Na type CON zeolite. Next,the zeolite was subjected to ion exchange twice with a 1 M aqueoussolution of ammonium nitrate at 80° C. for 1 hour, dried at 100° C., andthen calcined at 500° C. for 6 hours in an air stream to obtain aprotonic CON zeolite. The total acid content determined by NH₃-TPD was1.1 mmol/g. An evaluation of the adsorption performance as a hydrocarbontrapping material was carried out by the above toluenetemperature-programmed desorption measurement. Furthermore, in order toevaluate the hydrothermal stability, a steam treatment was conducted at800° C. and H₂O/Air=10/90 vol % for 5 hours, and then a toluenetemperature-programmed desorption measurement was similarly carried out.The results are shown in Table 6 and FIG. 8.

Comparative Example A2

With respect to a protonic BEA zeolite (Si/Al₂=25, Reference Catalyst ofCatalysis Society of Japan, JRC-Z-HB25), toluene temperature-programmeddesorption measurements were conducted identically with Example A18before and after the steam treatment. The results are shown in Table 6and FIG. 9.

Example A19

The CON zeolite (Si/Al₂=19) obtained in Example A5 was treatedidentically with Example A18 to obtain a protonic CON zeolite. The totalacid content determined by NH₃-TPD was 0.75 mmol/g. An evaluation of theperformance as a hydrocarbon trapping material was carried out by atoluene temperature programmed-desorption measurement as describedabove. The results are shown in Table 6 and FIG. 10.

Comparative Example A3

A hydrothermal synthesis was carried out with the same composition andsynthesis conditions as Preparation Example A to prepare [B,Al]-CIT-1(Si/Al₂=513, and Si/B₂=48), which was treated in the same manner as inExample A18 to obtain a protonic CON zeolite. An evaluation of theperformance as a hydrocarbon trapping material was carried out by atoluene temperature-programmed desorption measurement as describedabove. The results are shown in Table 6 and FIG. 10.

TABLE 6 Toluene Desorption Before/After desorption end Steam amounttemperature Zeolite treatment (mmol/g) (° C.) Example A18 CON zeoliteBefore 2.2 330 (Si/Al₂ = 31) After 1.4 296 Comparative BEA zeoliteBefore 2.1 330 Example A2 (Si/Al₂ = 25) After 1.0 290 Example A19 CONzeolite Before 1.9 390 (Si/Al₂ = 19) Comparative CON zeolite Before 1.7280 Example A3 (Si/Al₂ = 513)

In Example A18, the CON zeolite with Si/Al₂=31 exhibited a toluenedesorption amount (hereinafter referred to as “adsorption amount”) of2.2 mmol/g in the fresh state (before a steam treatment), and 1.4 mmol/gafter a steam treatment. On the other hand, in Comparative Example A2,the BEA zeolite with Si/Al₂=25 exhibited a toluene adsorption amount of2.1 mmol/g in the fresh state and 1.0 mmol/g after a steam treatment.When the toluene adsorption amounts before and after the steam treatmentwere compared, in Comparative Example A2 it decreased to 48%, while inExample A18, it secured 64%. This indicates that the CON zeolite ofExample A18 has higher steam stability compared to the BEA type zeoliteexhibiting an equivalent toluene adsorption amount.

Meanwhile, in Example A19, the CON zeolite with Si/Al₂=19 exhibited atoluene adsorption amount of 1.9 mmol/g and a desorption end temperatureof 390° C. in the fresh state. On the other hand, the CON zeolite havingSi/Al₂=513 in Comparative Example A3 prepared by a publicly known methodexhibited a toluene adsorption amount of 1.7 mmol/g and a desorption endtemperature of 280° C. When the toluene adsorption amounts and thedesorption end temperatures are compared, it becomes clear that the CONzeolites of Examples A18 and A19 exhibit a higher toluene adsorptionamount as well as a higher desorption end temperature.

As obvious from the above results, a CON zeolite of the presentembodiment exhibits a high adsorption amount and high steam stability,therefore it may be favorably used as an adsorbent, particularly as anadsorbent for a hydrocarbon component (such as an automobile hydrocarbontrapping material). Further, since the CON zeolite of the presentembodiment has a high acid content and high steam stability, it isbelieved to be also applicable to an exhaust gas treatment catalystrequired to have high acid content and high steam stability similarly tothe adsorbent.

INDUSTRIAL APPLICABILITY

A zeolite catalyst according to the present invention may be applicableto a catalyst for producing selectively a lower olefin, such aspropylene and butene, from a raw material containing methanol and/ordimethyl ether.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

1. A CON zeolite, silicon and aluminum in a molar ratio of aluminum tosilicon of 0.04 or more and the framework is CON as per the codespecified by the International Zeolite Association (IZA).
 2. The CONzeolite according to claim 1 having a crystal of polymorph B.
 3. The CONzeolite according to claim 1, wherein the molar ratio of aluminum tosilicon is higher than 0.08.
 4. A method of producing a zeolite of thetype CON as per the code specified by the International ZeoliteAssociation (IZA) by hydrothermal synthesis of a mixture comprising asilicon source, an aluminum source, an alkali metal element sourceand/or an alkaline earth metal element source, an organicstructure-directing agent, and water, wherein the molar ratio ofaluminum to silicon in the mixture is higher than 0.01.
 5. The method ofproducing a CON zeolite according to claim 4, wherein the zeolite has acrystal of polymorph B.
 6. The method of producing a CON zeoliteaccording to claim 4, wherein the molar ratio of aluminum to silicon inthe mixture is 0.08 or more.
 7. A CON zeolite obtained by the method ofaccording to claim
 4. 8. A catalyst for producing a lower olefin or anaromatic hydrocarbon containing the CON zeolite according to claim
 1. 9.A catalyst for producing a lower olefin or an aromatic hydrocarboncontaining the CON zeolite according to claim
 2. 10. A catalyst forproducing a lower olefin or an aromatic hydrocarbon containing the CONzeolite according to claim
 3. 11. A catalyst for producing a lowerolefin or an aromatic hydrocarbon containing the CON zeolite accordingto claim
 7. 12. An adsorbent containing the CON zeolite according toclaim
 1. 13. An adsorbent containing the CON zeolite according to claim2.
 14. An adsorbent containing the CON zeolite according to claim
 3. 15.An adsorbent containing the CON zeolite according to claim
 7. 16. Anexhaust gas treatment catalyst containing the CON zeolite according toclaim
 1. 17. An exhaust gas treatment catalyst containing the CONzeolite according to claim
 2. 18. An exhaust gas treatment catalystcontaining the CON zeolite according to claim
 3. 19. An exhaust gastreatment catalyst containing the CON zeolite according to claim 7.